Welcome to the MacNN Forums.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Desktops > RAID choices

RAID choices (Page 2)
Thread Tools
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Jan 12, 2008, 11:20 AM
 
does the RT5e just support IDE drives while the RTX-400 support SATA drives up to 4x1T?
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Feb 29, 2008, 10:28 AM
 
hi, finally we get a " two 3.2GHz quad core, 4 T storage, 4g ram mac pro and RAID card" as our server, but question is :
if i set RAID 5 using all 4 drives ( each 1T), then usable storage space for my data will be as mentioned before : (4-1)x1T = 3T.
but in this configuration, are there any "spare drive" in the computer so that if any one drive fails and will be automatically replace it, or there 'll be no spare drive in the mac pro and i need to replace the failed drive with a new one ASAP even though 1drive cannot be used to store data as from above calculation?

thanks
     
OreoCookie
Moderator
Join Date: May 2001
Location: Hilbert space
Status: Offline
Reply With Quote
Feb 29, 2008, 10:38 AM
 
There is one spare drive (which accounts for the 1 TB in capacity you cannot use). If one drive fails, you should replace it immediately, though.
I don't suffer from insanity, I enjoy every minute of it.
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Feb 29, 2008, 11:23 AM
 
thanks for prompt reply,
sorry but one more question :
says, if all drives in RAID 5 in above configuration are working perfectly smooth and full in storage, and i need to replace 3 new drives, then what 'll happen to my startup volume,e.g. macOS, and relevant softwares? as all these are also stored in the 3 drives that i ve been using ......., do i need to reinstall the whole lots of softwares and macOS again ? or can i copy those files to the " spare drive" before replacing the 3 used ones ?

thanks again
     
OreoCookie
Moderator
Join Date: May 2001
Location: Hilbert space
Status: Offline
Reply With Quote
Feb 29, 2008, 11:25 AM
 
If you want to add different drives, this will break your RAID5, unless you want to restore your system config.

So you cannot replace more than one drive, but even if you replace it with a larger drive, you cannot use the additional capacity in any way. If you remove three drive, then your startup volume (which resides on all 4 disks) won't work any longer and your data is lost unless you pop the old drives back in.
I don't suffer from insanity, I enjoy every minute of it.
     
ninahagen
Mac Enthusiast
Join Date: Mar 2007
Location: Kyoto, Japan
Status: Offline
Reply With Quote
Mar 1, 2008, 05:19 AM
 
I would install one of the 1TB drives, the one you use as you RAID5 backup/rebuild volume, in second opitical bay, connected with a wire harness to a PCIe Card.

Serial Attached SCSI Adapter - ExpressSAS H308 | ATTO Technology

Then I would put a Western digital 150GB Raptor in Bay 1, exclusively for system software & apps.

In bays 2~4 you'd have your main RAID volume.

Hope that helps.

Nina
     
mduell
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Mar 1, 2008, 12:56 PM
 
You don't need a SAS card to put a 1TB drive in the optical bay; in fact, it doesn't help to have one. Just plug the 1TB drive into one of the extra SATA ports on the logic board.
     
ninahagen
Mac Enthusiast
Join Date: Mar 2007
Location: Kyoto, Japan
Status: Offline
Reply With Quote
Mar 1, 2008, 02:01 PM
 
Originally Posted by mduell View Post
Just plug the 1TB drive into one of the extra SATA ports on the logic board.
Oops, thanks Mark that was the wrong link. Here is the right one, for a harness to connect SATA:

NewerTech� eSATA Extender Cable

With this harness, you can connect 6 SATA drives.

How about:

Optical Drive Bay: 150GB Raptor system drive: Only files & apps
Bays 1~4: 4 x 1TB HDs as your main RAID volume
External: 1 x 1TB HD as your RAID5 Rebuild/backup volume

Nina
( Last edited by ninahagen; Mar 14, 2008 at 12:42 PM. )
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Mar 14, 2008, 10:55 AM
 
hi, are there any suggestion for an external RAID storage solution for a mac book pro ?
preferably SATA drives ( so need eSATA in a mac book pro and a PCI express card as well), RAID 5, with available storage of ~2T space, as i would like this as a server in addition to the "macpro" config. mentioned above,
well, some mentioned about wiebetech RT5e, but seems it support IDE drive only but not SATA drives.

thanks
     
ninahagen
Mac Enthusiast
Join Date: Mar 2007
Location: Kyoto, Japan
Status: Offline
Reply With Quote
Mar 14, 2008, 12:40 PM
 
How did you solve your previous RAID 5 + Mac Pro issue?
     
OreoCookie
Moderator
Join Date: May 2001
Location: Hilbert space
Status: Offline
Reply With Quote
Mar 14, 2008, 05:04 PM
 
The harddrive interface doesn't have an impact on the speed of the RAID.
I don't suffer from insanity, I enjoy every minute of it.
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 14, 2008, 06:06 PM
 
Originally Posted by OreoCookie View Post
The harddrive interface doesn't have an impact on the speed of the RAID.
But what we care about is overall speed/throughput, and for that the interface is very important.

-Allen Wicks
     
mduell
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Mar 14, 2008, 06:22 PM
 
Originally Posted by benz View Post
hi, are there any suggestion for an external RAID storage solution for a mac book pro ?
preferably SATA drives ( so need eSATA in a mac book pro and a PCI express card as well), RAID 5, with available storage of ~2T space, as i would like this as a server in addition to the "macpro" config. mentioned above,
well, some mentioned about wiebetech RT5e, but seems it support IDE drive only but not SATA drives.
Since you only need 2TB, may I suggest RAID01? It allows for much cheaper enclosures and you come out ahead on price even with the extra drive.

I like the Newegg.com - AMS DS-2340SES eSATA VENUS T4S External Enclosure - Retail, although the 5 drive model is only another $50 and allows for a hot spare disk. You'll need to buy a Port Multiplier capable ExpressCard to go with it.
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Mar 14, 2008, 10:48 PM
 
"How did you solve your previous RAID 5 + Mac Pro issue?" ---------------

Our mac pro config. is " two 3.2GHz quad core, 4 T storage, 4g ram mac pro and RAID card. " i.e. Jan. 2008 version, i intend to use the fastest CPU available and use all four hard drives bay in mac pro, with the RAID card ( it's an option item), i choose RAID 5 with no spare disc, turn out 2.3T available storage, and also need to create a boot up volume for mac OS, i set it for 100Gb. so there are 2 volumes in the RAID set, i for mac OS and necessary software, and another volume is for data storage, well, the setting is not very difficult, just follow the instruction in " RAID utility" , but need time to build the RAID set, ~6hrs. it works very well. i have chosen using up all 4 drives for RAID set , so leaving none for spare drive, ..
but the new issue is that we want more secure data management for data, so besides disc backup ( we are tired of this), we plan to build another " cheap" server, as we get one more macbook pro here, so plan to connect with external HD RAID set , place it another building other than the mac pro server, use "autorouting" in OsiriX, then once we back up data to mac pro server, it automatically transfer data to the " new server" .
thanks for above advice, i have seen the "Newegg.com - AMS DS-2340SES eSATA VENUS T4S External Enclosure - Retail", but seems just RAID 0, 1, cooling may be issues especially the HDs, and also installation issues as from the user comments in the websites provided" ...

I am looking for wiebetech RT5/ RT5e,as suggsted by moderator, but one basic question to ask:
RT5 just support IDE drive, so shall i choose SATA drives if possible instead? what's dfference between the two?
also as i plan to connect the extrenal RAID set to "mac book pro", i tried a PCI express card for eSATA, but seems not very stable indeed, but for USB transfer it's more stable, any view on this ( eSATA in MAC BOOK PRO?)
or " USB/FW, RAID 5 set/ SATA drives/ macbook pro" a better option than eSATA?

thanks a lot for all advices provided
benz
     
OreoCookie
Moderator
Join Date: May 2001
Location: Hilbert space
Status: Offline
Reply With Quote
Mar 15, 2008, 02:56 AM
 
The difference between PATA (=IDE) and SATA drives is just the interface of the drive, the harddrive is the same. IDE drives are not slower than their SATA version, but IDE drives are getting rare.

Connecting the RAID via USB is pointless, really, really pointless, you'd have to use eSATA to get speeds that justify your investment in a RAID.
I don't suffer from insanity, I enjoy every minute of it.
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Mar 15, 2008, 09:55 AM
 
why is it pointless to use RAID in USB? is it because RAID will further slow down the data transfer rate ?

yes, i plan to use eSATA in mac book pro, but mine (unitek express Card/34mm) in mac book pro seems not very stable, any suggestion? what about Caldigit FASTA -1ex express card?

well, will the IDE drives totally fade off/ difficult to find 2-3yrs later?

benz
     
ninahagen
Mac Enthusiast
Join Date: Mar 2007
Location: Kyoto, Japan
Status: Offline
Reply With Quote
Mar 15, 2008, 10:44 AM
 
Originally Posted by OreoCookie View Post
The difference between PATA (=IDE) and SATA drives is just the interface of the drive, the harddrive is the same. IDE drives are not slower than their SATA version, but IDE drives are getting rare.

Connecting the RAID via USB is pointless, really, really pointless, you'd have to use eSATA to get speeds that justify your investment in a RAID.
Would a PCIe card attached to the RAID give decent results in a Macbook Pro?
     
OreoCookie
Moderator
Join Date: May 2001
Location: Hilbert space
Status: Offline
Reply With Quote
Mar 15, 2008, 02:07 PM
 
If you use a PCIe adapter, all harddrives work at native speed, there'll be no difference if you were to plug it into a Mac Pro, unless the transfer rate exceeds 250 MB/s (which is the limit of PCIe cards on notebooks).

@benz
No, it won't be slower because of the RAID, it'll be slow, because it's USB 2.0. Plus, you cannot have volumes larger than 2 TB with USB 2.0. (That's why there are two different RT5 models, the one with less connections doesn't have this limit as it doesn't have to be compatible with USB 2.0.) Come to think of it, the 2 TB restriction is probably a serious for you.
I don't suffer from insanity, I enjoy every minute of it.
     
ninahagen
Mac Enthusiast
Join Date: Mar 2007
Location: Kyoto, Japan
Status: Offline
Reply With Quote
Mar 15, 2008, 03:15 PM
 
[QUOTE=OreoCookie;3622055]If you use a PCIe adapter, all harddrives work at native speed, there'll be no difference if you were to plug it into a Mac Pro, unless the transfer rate exceeds 250 MB/s (which is the limit of PCIe cards on notebooks).

That was enlightening... thanks.

— So, couldn't this route work as a solution for benz? (PCIe card + external RAID array?

— Also, the increasing rarity of IDE drives would be enough to scare me off the RT5e.
     
OreoCookie
Moderator
Join Date: May 2001
Location: Hilbert space
Status: Offline
Reply With Quote
Mar 15, 2008, 05:59 PM
 
Yes, in principle it'll work on any system with eSATA connectors. You're also right that many large-capacity drives are released only with SATA interface. However, the successor to the RT5e has a SCSI interface.
I don't suffer from insanity, I enjoy every minute of it.
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 16, 2008, 12:43 AM
 
Originally Posted by benz View Post
why is it pointless to use RAID in USB? is it because RAID will further slow down the data transfer rate ?
No, it is because USB on Macs is awful, a total bottleneck even for a slow single hard drive. You need eSATA or at least FW800 connection to take real advantage of the throughput benefits of RAID0 arrays. USB 2 has no appropriate usage in Mac hard drive connections if speed matters at all. USB is OK for off-hours slow backup only, but even then buying USB is usually inappropriate because IMO drives should be capable of multiple uses, not just for overnight backup.

Not too that "RAID" means redundant array of independent drives and there are many different RAID configurations, each with radically different performance. "RAID" by itself without descriptive suffix like RAID0, RAID0+1, RAID5, RAID10, etc. is usually incomplete.

-Allen Wicks
( Last edited by SierraDragon; Mar 16, 2008 at 12:53 AM. )
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Mar 16, 2008, 09:55 AM
 
well, i search in the internet that eSATA external storage systems with RAID 5 for mac book pro is uncommon or very expensive otherwise. one product i see is Caldigit S2vr duo, which claim support eSATA with FASTA-1ex pcie card,

even the S2VR duo just support RAID 0 or 1,

Wiebetech RT5 can support USB, FW or eSATA but only IDE drives
while RT5e just support eSATA though use SATA drives,
moreover, the reseller of wiebetech here in HK seems ignorant and knows nothing about the product and post sale support to the customer, that really scare me !!!!

once again, i am bit worried about the eSATA PCIe card in mac book pro, as mine not very reliable but not sure whether it 's issue of the PCIe card, or the cheap eSATA 2.5inch HD enclosure ?!!

benz

benz
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 21, 2008, 06:44 PM
 
Deleted by poster.
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 21, 2008, 06:46 PM
 
benz-

IMO repurposing a laptop as heavy server to RAID5 drives is probably a bad idea. Laptops sacrifice a lot from an engineering standpoint to gain portability. You are describing one of the few uses that I would suggest someone buy or repurpose a G5 tower for if they lack funds for a Mac Pro. And forget about RAID5; you do not need all that redundancy for a redundant system. Just get a tower with a $90 monitor and configure 3-4 drives as JBOD, or as RAID0 if you need the speed.

Good luck!

-Allen Wicks
     
EricTheRed
Dedicated MacNNer
Join Date: Jan 2007
Location: Minnesota
Status: Offline
Reply With Quote
Mar 24, 2008, 01:04 PM
 
Run server class 1 TB HDD WD RE2-GP drives.

They use less power, are a little quieter, have some features just for RAID applications, and screw up less often.

WD RE2-GP 1 TB SATA Hard Drives ( WD1000FYPS )

Western Digital's RE2-GP hard drive - The Tech Report - Page 1
     
mduell
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Mar 24, 2008, 03:01 PM
 
Originally Posted by EricTheRed View Post
Run server class 1 TB HDD WD RE2-GP drives.

They use less power, are a little quieter, have some features just for RAID applications, and screw up less often.

WD RE2-GP 1 TB SATA Hard Drives ( WD1000FYPS )

Western Digital's RE2-GP hard drive - The Tech Report - Page 1
Stay away from the RE2-GP (GreenPower) drives... they're really slow compared to the competition like the Hitachis Apple uses in the 1TB Time Capsule.
     
misterdna
Junior Member
Join Date: Aug 2004
Location: Venice, CA
Status: Offline
Reply With Quote
Mar 24, 2008, 03:24 PM
 
Originally Posted by mduell View Post
Stay away from the RE2-GP (GreenPower) drives... they're really slow compared to the competition like the Hitachis Apple uses in the 1TB Time Capsule.
But what if speed isn't an issue? Still stay away from these drives?
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 24, 2008, 07:47 PM
 
Originally Posted by misterdna View Post
But what if speed isn't an issue? Still stay away from these drives?
IMO speed should always be an issue. The drive one uses today for overnight backup may be used for something different next week.

-Allen Wicks
     
misterdna
Junior Member
Join Date: Aug 2004
Location: Venice, CA
Status: Offline
Reply With Quote
Mar 24, 2008, 08:58 PM
 
Originally Posted by SierraDragon View Post
IMO speed should always be an issue. The drive one uses today for overnight backup may be used for something different next week.

-Allen Wicks
Eek, grim news for these power-saving drives!

Allen, have you set-up a new RAID-equipped Mac Pro yet? There was so much discussion on some other threads over a month ago, but I haven't seen any reports from people who've actually set-up a new Mac Pro with an internal RAID yet. I think I am about to pull the trigger on a new Mac Pro myself...
     
EricTheRed
Dedicated MacNNer
Join Date: Jan 2007
Location: Minnesota
Status: Offline
Reply With Quote
Mar 25, 2008, 01:22 AM
 
Originally Posted by mduell View Post
Stay away from the RE2-GP (GreenPower) drives... they're really slow compared to the competition like the Hitachis Apple uses in the 1TB Time Capsule.
I care about reliability over speed.
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 25, 2008, 01:30 PM
 
Originally Posted by EricTheRed View Post
I care about reliability over speed.
All hard drives fail. Repeat: all hard drives fail. Security in data handling is not achieved by small increments of reliability one drive vis-a-vis another drive, it is achieved by data redundancy for when (not if) drives fail or are stolen.

I too care about general reliability and try to buy higher end hardware to that end. However speed (all the various definitions thereof) is also important, and speed and reliability are not mutually exclusive.

-Allen Wicks
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 25, 2008, 01:32 PM
 
Originally Posted by misterdna View Post
Allen, have you set-up a new RAID-equipped Mac Pro yet? There was so much discussion on some other threads over a month ago, but I haven't seen any reports from people who've actually set-up a new Mac Pro with an internal RAID yet. I think I am about to pull the trigger on a new Mac Pro myself...
I ended up repurposing a 2006 Mac Pro instead of buying a new MP. I am currently still in the process of configuring it, but have added 4x2GB RAM, 2 x 1 TB Seagate hard drives and an HD 2600 XT graphics card. For financial reasons (and lack of drives with more than 1 TB capacity) I still have only 3 internal drives installed and hence have not configured RAID0 yet.

It turns out that the HD 2600 XT graphics card requires Leopard and I am still using 10.4.11 (because of Adobe incompatibilities with 10.5.2), so currently the box is running on the 7300 GT card. Also, I could not get the 7300 card out of the MP; either the release lever is defective or I do not understand the proper direction to push the lever (from Apple's instruction page). If anyone knows, please advise which direction (based on the orientation of a standing MP, looking in from the open side) does the release lever get pushed: up or down? Or some other direction, like right, left, forward or back?

The MP is in use now, and it seems that the hard drive setup, already half full, is indeed limiting for Aperture, as is the 7300 card. I will complete the upgrade to RAID0, Leopard and full usage of the 2600 card after I learn how to extract the 7300 card and not until April or May, another billing cycle for me.

-Allen Wicks
( Last edited by SierraDragon; Mar 25, 2008 at 02:00 PM. )
     
ninahagen
Mac Enthusiast
Join Date: Mar 2007
Location: Kyoto, Japan
Status: Offline
Reply With Quote
Mar 25, 2008, 01:51 PM
 
Originally Posted by SierraDragon View Post
All hard drives fail. Repeat: all hard drives fail. Security in data handling is not achieved by small increments of reliability one drive vis-a-vis another drive, it is achieved by data redundancy for when (not if) drives fail or are stolen.

I too care about general reliability and try to buy higher end hardware to that end. However speed (all the various definitions thereof) is also important, and speed and reliability are not mutually exclusive.

-Allen Wicks

Well said.
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Mar 28, 2008, 10:50 AM
 
Originally Posted by misterdna View Post
Eek, grim news for these power-saving drives!

Allen, have you set-up a new RAID-equipped Mac Pro yet? There was so much discussion on some other threads over a month ago, but I haven't seen any reports from people who've actually set-up a new Mac Pro with an internal RAID yet. I think I am about to pull the trigger on a new Mac Pro myself...
well, i started this threads, and i finally make a server by config. a mac pro ( Jan. 2008) as mentioned before in this thread, the config. is :
2 3.2Ghz quad core CPU, 4G RAM, 4T storage ( each 1 T HDs), RAID card, dual DVD burner ( we seldom use though), set at RAID 5 by using all 4 drives, with 2.3 T available storage, create 1 volume for mac OS, then other available space for data storage, i haven't get a spare drive instead ( i think it's not effective for sparing a drive ), the RAID setting is easy , just follow instruction from RAID utility pdf from mac, so far so good, though the input of data is gradual , about 6-7Gb/ week.
i also agree with what allens says " speed and reliability is not mutually exclusive" , and i agree that macbook pro may not be the optimal tool for server, or massive storage purpose, but as we just get a spare macbook pro, so just want to use it to optimize our server systems, but now plan to have another set of macpro, put it in another physical space, as a back up servers with RAID, so no more disc burning, and also can cover both the hardware or software crashes in the system,
that 's my thinking

benz
     
misterdna
Junior Member
Join Date: Aug 2004
Location: Venice, CA
Status: Offline
Reply With Quote
Mar 28, 2008, 12:44 PM
 
Originally Posted by benz View Post
well, i started this threads, and i finally make a server by config. a mac pro ( Jan. 2008) as mentioned before in this thread, the config. is :
2 3.2Ghz quad core CPU, 4G RAM, 4T storage ( each 1 T HDs), RAID card, dual DVD burner ( we seldom use though), set at RAID 5 by using all 4 drives, with 2.3 T available storage, create 1 volume for mac OS, then other available space for data storage, i haven't get a spare drive instead ( i think it's not effective for sparing a drive ), the RAID setting is easy , just follow instruction from RAID utility pdf from mac, so far so good, though the input of data is gradual , about 6-7Gb/ week.
benz
So by a "volume" you mean you will make a partition across the RAID for the system? Some people seem dead-set against the system being part of the RAID, though I see a number of people don't have a problem with it (based on looking at MacRumors boards yesterday).

I've been looking at RAID ideas a lot lately, and am still unsure what I will do. My high end set-up idea is a similar RAID 5 system to yours, but with a separate boot drive (Raptor?) in the 2nd optical disc spot... My low end idea is no RAID but still a number of drives so that files, system and scratch are each on a separate drive. And I have a dozen ideas between the two. Damn it's hard for me to figure out what will give me the most bang for my buck (even after participating in a coupe of RAID threads a month or so back). Thanks to all for your teachings.
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Mar 29, 2008, 08:54 AM
 
"So by a "volume" you mean you will make a partition across the RAID for the system? Some people seem dead-set against the system being part of the RAID, though I see a number of people don't have a problem with it (based on looking at MacRumors boards yesterday)."------

yes, by using the RAID utility in macpro Mac OS, u can easily create volumes, and i create a boot up volume ( sized 100G) containing Mac OS, and other space for data volume , both volumes are in the RAID set at RAID 5. but u need a RAID card installed in the mac pro, which costs ~800USD, so it's hardware RAID, but one point i think it lacks is "e mail notification of the failed drive" , that some other RAID solutions such as Caldigit provides
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 30, 2008, 02:08 AM
 
Originally Posted by benz View Post
"So by a "volume" you mean you will make a partition across the RAID for the system? Some people seem dead-set against the system being part of the RAID, though I see a number of people don't have a problem with it (based on looking at MacRumors boards yesterday)."------

yes, by using the RAID utility in macpro Mac OS, u can easily create volumes, and i create a boot up volume ( sized 100G) containing Mac OS, and other space for data volume , both volumes are in the RAID set at RAID 5. but u need a RAID card installed in the mac pro, which costs ~800USD, so it's hardware RAID, but one point i think it lacks is "e mail notification of the failed drive" , that some other RAID solutions such as Caldigit provides
IMO putting the OS on a RAID array is simply not a good idea.

-Allen Wicks
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Mar 30, 2008, 04:50 AM
 
why?
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 30, 2008, 12:36 PM
 
Originally Posted by benz View Post
why?
Sorry, I don't have the time and energy to dissertate on why (you will have to do your own homework), but basically RAIDs are complex and IMO for some things simple is better. When it comes down to it, for most of us MPs are single-user desktop (albeit powerful) personal computers. If MPs were engineered with 10 internal drive bays I might have a different opinion.

-Allen Wicks
( Last edited by SierraDragon; Mar 30, 2008 at 12:44 PM. )
     
ninahagen
Mac Enthusiast
Join Date: Mar 2007
Location: Kyoto, Japan
Status: Offline
Reply With Quote
Mar 30, 2008, 01:43 PM
 
I don't understand the interference issues either. I just took it on faith from more experienced members. Still, it would be nice to know why. Anybody?

One thing I can think of is that in a 4 drive RAID array, when one drive failed, the OS would go down with the data. Wouldn't that make it a pain to reboot (and in the case of RAID 5) to rebuild your data?

Also, Mark Duell mentioned some potential firmware conflicts awhile back.

Nina
     
misterdna
Junior Member
Join Date: Aug 2004
Location: Venice, CA
Status: Offline
Reply With Quote
Mar 30, 2008, 01:47 PM
 
Originally Posted by SierraDragon View Post
Sorry, I don't have the time and energy to dissertate on why (you will have to do your own homework), but basically RAIDs are complex and IMO for some things simple is better. When it comes down to it, for most of us MPs are single-user desktop (albeit powerful) personal computers. If MPs were engineered with 10 internal drive bays I might have a different opinion.

-Allen Wicks
Allen, I too have been trying to do my own homework to find detailed and current information on why not to put the boot drive on a RAID, specifically with the 2008 Mac Pro and RAID card. I tend to believe the recommendation, since so many of you technically informed commenters on NNForums recommend not booting from a RAID. However, very little detail has been given as to why. I have been spending a ridiculous number of hours trying to research RAID set-ups so I can make a decision for my soon-to-be-purchased Mac Pro, but I still haven't found much explanation on this detail, just some people broadly saying it isn't a good idea. Meanwhile, I've also found plenty of commenters on various forums who do boot from RAID 5 arrays on their new Mac Pros (not that this means it's wise, but it also isn't uncommon). I've also found plenty of technical discussions on how to set-up RAID boot volumes on Mac from people far more expert than I am, and most of the threads have zero comments about booting from a RAID being unwise (when there are comments saying it's not wise, they never seem to have any details). So, with the difficulty I've had researching this, I really can't fault BENZ for asking you "why."

Doing a lot of searching outside NNForums, the few things I've found are:

Bare Feats thought it worthy to speed test RAID 0 boot volumes.
Best boot drive for the Mac Pro?

What I get from this: A trusted testing site testing RAID 0 boot volumes makes me think the idea must have some merit.


An older discussion of booting from a software RAID is here:
MacSlash | Can I Boot From RAID On A Mac Pro?

What I get from this: Firmware updates require booting from a non-RAID drive, which doesn't seem like a big deal. Some people agree that adding the complexity of a RAID to a boot volume is a bad idea (though I really hoped to find detailed explanation and/or evidence -- maybe it's just self-evident to advanced tech people, or to people with RAID experience, but it's not self-evident to me).


When I posted the question on another NNForum thread, the only reply I got was from mduell, and the only reason he gave was (possibly) not being able to update firmware when booted from the RAID:
http://forums.macnn.com/65/mac-pro-a...o/#post3630339


Anyway, I have really been trying to do my homework, but have yet to find current and explicit details on why booting from a RAID is unwise. I can't tell if it just sounds scary to RAID the boot drive because of the mixture of two highly complex systems, or if there's real evidence that RAIDing the boot drive causes problems that are more difficult to recover from (and this is all based on the assumption of a diligent back-up plan). It's really hard for me to tell what is going on because I just can't find details... Again, maybe it's self-evident to you experts and I'm just not knowledgeable enough to see it for what it is. If detailed information exists, can someone help point me in the right direction? This is the single area relating to RAIDs that I see a lot of opinions on, but very little details given to support the opinions.
( Last edited by misterdna; Mar 30, 2008 at 01:54 PM. Reason: fixing typos... always fixing typos)
     
ninahagen
Mac Enthusiast
Join Date: Mar 2007
Location: Kyoto, Japan
Status: Offline
Reply With Quote
Mar 30, 2008, 03:06 PM
 
Thanks mrdna, I appreciated the thoughtful post & the barefeats best boot drive link.

As I understand it, RAID volumes can be partitioned into dedicated stripes. Two questions arise from that:

— Wouldn't making a formal partition insulate from the OS/data interaction issues raised?

— I personally would love to use this concept to get a faster scratch drive volume across four drives in RAID0... optimal?

We have been buying computer gear for another partner, so our designer is still on her G5 Quad 2.5. We want to move up to the MP soon, but having been unresolved about RAID configurations.

If RAIDing the boot and scratch made sense, we would love to configure ours as follows:

3.2 Ghz Octo
8GB RAM (we use mainly Adobe Creative Suite)
4 x 450GB 15k rpm Seagate Cheetahs in RAID0 in 3 partitions:

Partition 1: Boot = 150GB
Partition 2: Scratch = 300GB
Partition 3: Data = 1TB

Backup: 1TB Time Capsule

If this discussion shows booting from a RAID to be too problematic, it could still work for a 450GB scratch, in which case, the boot drive could go in the extra optical bay.

Would love to hear about this from some of our members.

Nina
( Last edited by ninahagen; Mar 30, 2008 at 03:20 PM. )
     
misterdna
Junior Member
Join Date: Aug 2004
Location: Venice, CA
Status: Offline
Reply With Quote
Mar 30, 2008, 04:06 PM
 
Originally Posted by ninahagen View Post
Thanks mrdna, I appreciated the thoughtful post & the barefeats best boot drive link.

As I understand it, RAID volumes can be partitioned into dedicated stripes. Two questions arise from that:

— Wouldn't making a formal partition insulate from the OS/data interaction issues raised?
Thank you Nina. BTW, my relatively non-expertise understanding is that people object to the basic concept of setting up a Mac so it's booting from a RAID, rather than taking issue specifically to any "OS/data interaction." But, of course, I could be wrong...
     
mduell
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Mar 30, 2008, 06:27 PM
 
I have no problem with booting from a RAID array. Most of my servers boot from 2 or 3 drive RAID1 arrays. It's just important to be advised that it can cause some hassle and headaches down the road.
     
misterdna
Junior Member
Join Date: Aug 2004
Location: Venice, CA
Status: Offline
Reply With Quote
Mar 30, 2008, 07:26 PM
 
Originally Posted by mduell View Post
I have no problem with booting from a RAID array. Most of my servers boot from 2 or 3 drive RAID1 arrays. It's just important to be advised that it can cause some hassle and headaches down the road.
Awww, now that's a tease if there's ever been one! It appears I'm going to have to beg...

Can you or anyone please give a few details types of hassles and headaches one is risking by booting from a RAID? Pretty please?

At the moment, the danger of booting from an array feels like some mysterious mythological beast to me -- many speak vaguely of risks, but no one will explain what the risks are. Like it's something you very advanced Mac people feel in your bones based on the sum of your knowledge and experience, but yet it can't put into words. For less knowledgeable people like myself, it's really hard to evaluate the risks vs. rewards when the risks are never discussed, only alluded to. Knowing any specific details on the type of risks and/or the odds of incurring such risks when booting from a RAID would really help me (and possibly others?) make a decision on how to set up my next Mac.

I apologize in advance if it seems like I'm beating a dead horse. Please ignore me if that's the case...

(I am assuming that the possibility of having to boot the Mac from a non-RAID drive to perform a firmware update is not a headache you speak of, since that doesn't seem to be much of an issue)
( Last edited by misterdna; Mar 30, 2008 at 07:32 PM. Reason: Added parenthese at the end)
     
benz  (op)
Forum Regular
Join Date: Nov 2003
Location: HK
Status: Offline
Reply With Quote
Mar 30, 2008, 10:55 PM
 
well, i hive no idea of the boot up volume issue, that why i ask "why? " just want to learn and open scope of this scenario, but my preliminary impression is that it works smoothly so far from my config. as mentioned above. i don't know the answer of OS/ data interaction, but intuitively think that the worry may be due to fault drives if any, happens that RAID has to rebuild the lost data from other striped and potentially problematic if even the OS needed to be rebuild from RAID , i.e. the RAID cannot find a OS platform to do what it supposes to do. But if so, can we install the OS boot disc and use the disc/ RAID utility ?
i don't know the answer again

benz
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 31, 2008, 01:28 PM
 
Originally Posted by misterdna View Post
...Can you or anyone please give a few details types of hassles and headaches one is risking by booting from a RAID? At the moment, the danger of booting from an array feels like some mysterious mythological beast to me -- many speak vaguely of risks, but no one will explain what the risks are.
No mythology and no rocket science and it has been discussed; and google info, Wiki, etc. have lots of info on RAID consequences. It is just a matter of putting one's proposed MP configuration on paper (including what type of RAID arrays) like Nina did a few posts ago, doing homework and then making one's decisions. And then changing the plan as available hardware and user needs change.

• MPs have only 4 drive bays, meaning that is the heat, power supply, etc. that Apple designed the box for. Each user must decide how he/she intends to use the finite heat/power supply issues. Adding RAM, multiple displays, advanced graphics cards, multiple fast max-sized hard drives, etc. all have engineering consequences. Some may want to exceed Apple's design spec, sacrifice what might be a Blu-ray optical drive slot and install a maximum of 5 internal 1 TB or larger hard drives.

• Fast (spindle speed) hard drives add cost/GB, probably heat and usually provide much lower capacity.

• RAID0 (my personal choice) adds speed and maximum capacity at the cost of if one striped drive fails the entire array goes down. Each added drive in a RAID0 array increases speed and increases the probability of failure. Simply put, 2 drives in RAID0 are ~2x as fast and have ~2x the probability of failure.

• To realize full RAID stripe potential drives should not exceed 50% full. That usable capacity number gets goes into the putting one's proposed MP configuration on paper discussed above. Nominal sizes are largely irrelevant; what matters is how full one plans to allow them to become.

• While we are looking at our proposed MP configuration on paper we answer questions:
- How many hard drives are available to array (important!)?
- How is backup done, onsite and off site?
- What happens as demands on capacity quadruple, like they always do?
- How do we recover from crashed arrays? How do we recover crashed OS? Recognizing the cost of recovery time (crashes always occur during critical deadlines).
- How easy is it to change the plan as available hardware and user needs change?
-Will we use the capacity-hog Time Machine?

I have maximum capacity needs and my intent is to try to stick with an internal HD setup for on site, so my personal conclusion is that a MP does not allow enough internal hard drives for safe-enough RAID of the OS drive when I ask what are the consequences of an on-deadline striped RAID OS crash. Note that with more drives my solution would be different.

All the above has been said before, and there are other relevant concepts previously discussed that I did not include. There is no right answer. Other folks with different needs will come to different solutions. In my experience choices become less confusing when we finish debating RAID theory and write down which drive does what.

-Allen Wicks
( Last edited by SierraDragon; Mar 31, 2008 at 01:57 PM. )
     
SierraDragon
Mac Elite
Join Date: Mar 2004
Location: Truckee, CA
Status: Offline
Reply With Quote
Mar 31, 2008, 02:16 PM
 
Originally Posted by ninahagen View Post
-----------------
4 x 450GB 15k rpm Seagate Cheetahs in RAID0 in 3 partitions:

Partition 1: Boot = 150GB
Partition 2: Scratch = 300GB
Partition 3: Data = 1TB

Backup: 1TB Time Capsule
----------------
Nina-

When I write down usable capacities rather than nominal capacities I get 4x450x50%= 900 GB to divide up. That works out to
-----------------
Partition 1: Boot = 150GB
Partition 2: Scratch = 300GB
Partition 3: Data = 450GB

Backup: 1TB Time Capsule (~850 GB available)
----------------

That may be enough capacity for your needs but not for mine. And that solution puts full reliance on Time Machine to recreate all apps, data and the OS after a catastrophic array crash. Time Machine is too new for me to give it such a critical function (not to mention that one of my most important apps, Aperture, has serious reported backup difficulties with TM).

Sure would be fast though...

-Allen Wicks
( Last edited by SierraDragon; Mar 31, 2008 at 02:25 PM. )
     
misterdna
Junior Member
Join Date: Aug 2004
Location: Venice, CA
Status: Offline
Reply With Quote
Mar 31, 2008, 03:20 PM
 
Originally Posted by SierraDragon View Post
No mythology and no rocket science and it has been discussed; and google info, Wiki, etc. have lots of info on RAID consequences. It is just a matter of putting one's proposed MP configuration on paper (including what type of RAID arrays) like Nina did a few posts ago, doing homework and then making one's decisions. And then changing the plan as available hardware and user needs change............
I kind of feel like I'm taking crazy pills. My only question is why not to boot from a RAID.

Allen, to be honest, it was one of your RAID posts from 3-4 months ago that got me turned on to this forum in the first place. I was a complete RAID newbie, and you seemed so knowledgeable and so willing to share your ideas. I took great joy in reading your posts, watching your many many RAID configuration ideas develop, reading others make suggestions, etc. It's been fascinating and educational watching the discussion by people more expert than myself (especially mduell & ninahagen), and being able to ask questions along the way when I didn't understand something.

And since I read that first post of yours 3-4 months ago, I truly believe I've read every RAID-related post on this forum made since that date, and I've also probably read all the links recommended. I also put in plenty of hours just searching for RAID info elsewhere. It's practically been an obsessive compulsion for me, trying to understand every detail of things I don't understand before committing to a configuration for my new Mac Pro. And for someone who's never used a RAID in my 19.5 years of earning a living with Macs as a graphic artist, I've read so much that I almost feel I've become an expert on the pros and cons of various internal RAID configurations for the new Mac Pros. Almost...

So as much effort as you put into this post of yours, I am sorry to say that you have only stated things that I have already learned (mostly from reading your posts). And while this post of yours should be required reading for people who are just getting their feet wet in the subject of RAIDs, it completely ignores my one and only question: why is it ill-advised to boot from a RAID?

And that's why I feel I'm taking crazy pills. Or that there is indeed some great mythology being perpetuated about not booting from a RAID. Because it's been said over and over, yet no one is given an explanation on why you can RAID everything else, but you're really asking for trouble if you RAID your boot drive...

I've done even more searching on the subject since my posts yesterday, and have found nothing more. I've seen the question posted in other forums with zero responses. So I just get really curious when I've seen a number of people say not to boot from a RAID, but no one will say why.

In my mind, a 4-drive single-volume RAID 5 array would be a very straight-forward set-up in the new Mac Pro, and I've read posts in various forums from people who are running this configuration. It seems like I could clone the single-volume RAID regularly to an external drive (actually two externals, which would be rotated). It seems so simple. If anything ever went wrong with the RAID, I could just start up from my external and I'd be instantly up and running with my work. I could fix the array as time permits, and then simply clone the external back to the single-volume RAID to be back to full-speed. I can see pros and cons of this set-up. But I can't help thinking about the mysterious assertion that you should not boot from a RAID, and wonder why that is such a great risk compared to other proposed RAID set-ups? No one is explaining the reasoning for this advice.

I realize there are inherent complications and risks associated with RAIDs. I got the feeling from a recent post of yours that the OS is complicated and RAIDs are complicated, and it's just asking for trouble to mix the two. Is it that simple? Is there evidence that this causes problems? Or for you Mac experts, does it just seem like it would cause problems? If that's the case, I tend to trust you experts, but just want to know where you're coming from when I weigh my options. Perhaps I should be more scared of RAIDS than I am, and not RAID anything beyond my scratch disk. But I don't want to operate from fear, I want to operate from knowledge. And the one thing I don't understand, and seemingly can't get an answer to is, why do some of you say with such confidence, when considering a Mac Pro internal RAID configuration, that you should not boot from a RAID? I figure there must be good reasons behind statements made without the slightest equivocation. This is the one piece of the RAID puzzle I don't get. It is the only answer I seek.
( Last edited by misterdna; Mar 31, 2008 at 03:50 PM. Reason: Because I'm compulsive, always finding a way to reword something)
     
mduell
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Mar 31, 2008, 03:20 PM
 
Originally Posted by misterdna View Post
Awww, now that's a tease if there's ever been one! It appears I'm going to have to beg...

Can you or anyone please give a few details types of hassles and headaches one is risking by booting from a RAID? Pretty please?

At the moment, the danger of booting from an array feels like some mysterious mythological beast to me -- many speak vaguely of risks, but no one will explain what the risks are. Like it's something you very advanced Mac people feel in your bones based on the sum of your knowledge and experience, but yet it can't put into words. For less knowledgeable people like myself, it's really hard to evaluate the risks vs. rewards when the risks are never discussed, only alluded to. Knowing any specific details on the type of risks and/or the odds of incurring such risks when booting from a RAID would really help me (and possibly others?) make a decision on how to set up my next Mac.
I'm not trying to be obtuse, I thought the risks of RAID were well known. Wikipedia has reasonable coverage of them.
The annoyance of losing the ability to boot your computer (for a time) because one or four drives failed is quite high in my book. Also should some part of the machine other than the RAID controller or a disk fail, you can't necessarily pull out the drives and stick them in another machine.
     
 
Thread Tools
 
Forum Links
Forum Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Top
Privacy Policy
All times are GMT -4. The time now is 07:23 AM.
All contents of these forums © 1995-2017 MacNN. All rights reserved.
Branding + Design: www.gesamtbild.com
vBulletin v.3.8.8 © 2000-2017, Jelsoft Enterprises Ltd.,