[devastHB]

hello, I should be getting my dual 2.8 next week, and will be removing the provided 320gig HD and attaching the following drives:

4 500gig HDs
1 1TB drive
2 Optical drives (1 of which is stock)

I also have an external firewire case for the optical drive and an external esata for one of the drives if necessary.

My Question is , what is the best way to configure this all???

Originally I was thinking of:

scenario 1: all 4x 500MB drives used in a 2TB raid 0 and the external 1TB drive as a 1TB time machine backup
int:
two top bays: 2x optical drives
lower 4 bays: 4x500drives
ext: 1 tb drive connected esata

OR

scenario 2: 3x 500MB drives used in a 1.5TB raid 0 and 500MB + 1TB in a JBOD 1.5TB time machine backup
int:
two top bays: 1x optical drive & 1x1TB drive (have a drive cage)
lower 4bays: 4x500drives
ext: optical drive connected firewire 400

I think I would prefer scenario 2 if its possible to configure a JBOD, but actually I'm not sure.

Any thoughts? TIA

[kupan787]

Just so you know (in case you don't) but the optical drives are PATA. So if you want to put a hard drive in the optical bay, it would need to be PATA if you are going to connect it to the existing connections.

[OreoCookie]

Using a RAID0 is not very safe, I strongly advise against it. A RAID0 or a JBOD must be avoided for backup drives! How much storage do you need? What are you using your ProMac for?

[devastHB]

I believe there are also 2 unused SATA connectors inside the mac pro, 1 which i'll put to the drive, another which I'll put onto an esata bracket

Originally Posted by kupan787 

Just so you know (in case you don't) but the optical drives are PATA. So if you want to put a hard drive in the optical bay, it would need to be PATA if you are going to connect it to the existing connections.

[devastHB]

I understand that the raid 0 array with 3 drives is 3x more prone to drive failure, but if there is a JBOD time machine backup of equal size backing up the stripped array, logically I don't have anything to worry about unless BOTH the RAID0 and the JBOD time machine go down, which would be really really rare.
The "restore from time machine" option on the leopard install disk takes away the risk of really losing the data in my POV, I guess the only downside is the downtime which will be the time it takes for me to run to bestbuy to pick up a replacement drive and restoring from the backup.

I'll be mainly using it with afx, premiere, I guess all of CS3, visualhub, handbrake, vmware fusion+XP+3D Max, MAMP, and some little apps.

Originally Posted by OreoCookie 

Using a RAID0 is not very safe, I strongly advise against it. A RAID0 or a JBOD must be avoided for backup drives! How much storage do you need? What are you using your ProMac for?

[Laurence]

If you have a RAID 0 array and one drive fails. I would recommend replacing all the drives in the array before restoring from the Time Machine backup. If the array's been running for a few years and one drive fails, the others are much more likely to go out sooner rather than later. As long as the array lasts a few years it will cost next to nothing to replace all the drives by then or more likely you'll want to increase the size of all the drives by then anyway.

[OreoCookie]

That's not correct, because your backup consists of a JBOD. And because it's done in software. If your startup volume breaks, your JBOD is broken, too, and you won't be able to recover your data from your Time Machine backup. So don't do it if your data is important to you.

Also, you might actually improve your speed when you create a dedicated RAID0 scratch array of two (fast) drives. Then your machine can simultaneously access the OS/apps drive and the scratch volume.

In any case, I strongly advise against your proposed solution. Instead, you should start by telling us how much storage space you need and how much of that needs to be backed up (backing up video files is not such a good idea at the moment as each time the file is changed, the whole file is copied; this will change when ZFS is adopted). I think a solution with fewer disks and possibly a scratch volume is actually more beneficial and safer at the same time.

[SierraDragon]

I deal with batches of DSLR capture, not video. My most likely solution at this point is basic SATA, system drive + 2x1TB RAID 0 (third party SoftRAID) + largest possible non-RAID 4th drive for onsite backup.

-Allen Wicks

[Tesselator]

Originally Posted by devastHB 

I understand that the raid 0 array with 3 drives is 3x more prone to drive failure, but if there is a JBOD time machine backup of equal size backing up the stripped array, logically I don't have anything to worry about unless BOTH the RAID0 and the JBOD time machine go down, which would be really really rare.
The "restore from time machine" option on the leopard install disk takes away the risk of really losing the data in my POV, I guess the only downside is the downtime which will be the time it takes for me to run to bestbuy to pick up a replacement drive and restoring from the backup.

I'll be mainly using it with afx, premiere, I guess all of CS3, visualhub, handbrake, vmware fusion+XP+3D Max, MAMP, and some little apps.

I agree with you and think that you're thinking correctly about this. Also the myth and
misunderstanding that RAID0 of 4 or 3 is 4 or 3 times more risky is really just that - a
misunderstanding and a bit of a myth.

If the environment is good (enough fan speed to keep them always BELOW 37c, no foot
pounding vibrations from wooden floors, etc. etc.) and they make it past the 3 week point
(where 80% fail if they going to) then there's really no credible reason to expect that your
RAID0 failure rate will be significantly different. It's NOT a linear multiplication like most
people saying these things would imply.

BTW, I like "scenario 1" but I dunno what Time Machine will act like with only half the
space of the target storage. AND... I don't really know Time Machine... it might be smarter
to use a real "back up" type of utility if indeed it can't restore like Mr. Cookie is saying.

[OreoCookie]

Originally Posted by Tesselator 

I agree with you and think that you're thinking correctly about this. Also the myth and misunderstanding that RAID0 of 4 or 3 is 4 or 3 times more risky is really just that - a misunderstanding and a bit of a myth.

It's not a myth, it's math. So let's just consider the risk of hardware failure. The risk of software failure is at least as important. Assume the risk that a harddrive fails over the period of a year is p. Take p = 5 % for the sake of argument. Then the probability that the drive is fine is (1-p) = 95 %. If you have 4 harddrives, then the probability that all drives will be fine after one year is (1-p)^4 = 81.5 %. This can be approximated by neglecting higher powers in p, i. e. 1-4p = 80 % -- the probability of hardware failure is roughly four times as high.

In solution 2, the failure of the backup was 100 % if the RAID0 fails (if your startup volume is borked, then your software JBOD with the backup on it is gone, too!). A failed system update or mistakes by users (let's add another disk to my RAID0 …) can lead to loss of data as well.

Originally Posted by Tesselator 

BTW, I like "scenario 1" but I dunno what Time Machine will act like with only half the space of the target storage. AND... I don't really know Time Machine... it might be smarter to use a real "back up" type of utility if indeed it can't restore like Mr. Cookie is saying.

Well, no backup solution can work if you want to backup more data than storage that is available. Sometimes it's smarter to do backups manually. I've used Synk in the past and I was very happy with it.

So IMO the OP should think about the amount of data he wants backed up and how he wants to back them up. One forum member (a photographer) uses harddrives for backups. He charges his clients for it and just stores the harddrive. I assume the OP doesn't need all his raw video files instantly available. So instead of `pimping', think about what you want to do, such a solution might actually be faster. Separating your startup/applications drive from your data storage drive is such a way: simultaneous access of both don't interfere with each other.

[ninahagen]

A question:

— Have you already bought those drives?

Some initial observations:

— The system drive should not be a RAID array. I have been all over this, and many people have counseled against it. If you want speed, a single WD Raptor (10k rpm, 150GB) or a single Seagate Cheetah (15k rpm, 300GB) should do nicely.

— You have to have much more memory for your time machine than your RAID array.

— Nothing wrong with RAID0 array if you back it up with at least another RAID0 array, and preferably with a RAID5. In either case, the back up should be able to be taken offsite. If you do this well enough, you can avoid using time machine altogether, save the drive bay for an extra HD for your RAID array (and since RAID zero scales almost linearly, you will really get a lot of zoom from that extra bay.

Some more questions:

— How much data do you have now?

— How much do you expect to have a year from now? Two years?

— What are the main apps you use?

— What is the size of a typical file you work on?

— Do you work on one file at a time, or multiple files?

— Do you run a single app at a time, or multiple apps?

Please let us know the answers to these questions. You are sure to get better help.

[MarkLT1]

Originally Posted by OreoCookie 

It's not a myth, it's math. So let's just consider the risk of hardware failure. The risk of software failure is at least as important. Assume the risk that a harddrive fails over the period of a year is p. Take p = 5 % for the sake of argument. Then the probability that the drive is fine is (1-p) = 95 %. If you have 4 harddrives, then the probability that all drives will be fine after one year is (1-p)^4 = 81.5 %. This can be approximated by neglecting higher powers in p, i. e. 1-4p = 80 % -- the probability of hardware failure is roughly four times as high.

Just to extend this a little further. In this example, with a probability of failure being 5% per year, with a RAID0 setup, the probability of losing ALL of your data is 1-81.5%, or 18.5%. On the other hand, if you are using 4 separate drives (non-RAID), the probability of losing ALL of your data (by losing all 4 drives) in a given year is 5%^4, or 0.000625%. If we figure out the probability of losing any combination of drives, we come up with the following:

P[1 drive failed] = 0.171
P[2 drives failed] = 0.00226
P[3 drives failed] = 0.000119
P[4 drives failed] = 0.00000625

From this we can find the expected data loss in a given year, assuming the data is evenly spread over the drives. In the case of the RAID0 setup, your expected loss is 0.185 or 18.5% of your data. In the case of individual drives, your expected losses are:
0.171*0.25 + 0.00226*0.5 + 0.000119*0.75 + 0.00000625*1.0 = 0.044, or about 4.4% data loss expected. In other words, your expected data losses over a 1 year period are actually greater than 4 times.

Now this example made some assumptions that may not be true in a "real world" setting at least initially (that you'd have your data evenly spread over the four drives). However, as time progresses, and your drives fill (and the hard drives age, and have a greater chance of failure) this becomes closer to what you'd be looking at.

This isn't to say RAID0 should never be used. But you must keep in mind that it carries a much higher risk of data loss, and have measures in place to mitigate this.

[OreoCookie]

Originally Posted by MarkLT1 

Just to extend this a little further. In this example, with a probability of failure being 5% per year, with a RAID0 setup, the probability of losing ALL of your data is 1-81.5%, or 18.5% If you are simply using 4 separate drives, the probability of losing ALL of your data (by losing all 4 drives) in a given year is 5%^4, or 0.000625%.

This is plainly incorrect. With RAID0, the data is striped across several drives and if one drive fails, you cannot reconstruct any data.

Originally Posted by storagereview

Fault Tolerance: None. Failure of any drive results in loss of all data, short of specialized data recovery.

Only on JBODs you can reconstruct data from the remaining drives, but even that doesn't work with OS X' implementation of JBODs!

[Tesselator]

But the entire math is flawed from the first. So really no amount of correct or incorrect calculation is going to make it any better. One problem comes from the fact that when (within the life period of the HDD unit) and under what conditions failure occurs. None of that is stated in manufacturers spec-sheets and it's all just averaged together. This might be OK-ish as thumb measurement for determining a very general human expectation for about how reliable a particular HDD model might be but it's totally unacceptable for any sort of extrapolations therefrom!

Then there are batch run variations! Manufacturers of any hard or mechanical devices will tell you that different batches vary in quality from run to run. Which batch was tested in order to ascertain the published spec? Was it a good run or a bad run? How many drives were even tested? Were any physical drive units actually tested at all or is it a hypothetical derivation like Seagate actually says it is. If the later (which is actually admitted) then that makes this specification even more meaningless.

So how intelligent is it to extrapolate a near totally meaningless spec. and then make claims and advisories based on that?

I would have to answer: Not very.

[Tesselator]

Originally Posted by OreoCookie 

Well, no backup solution can work if you want to backup more data than storage that is available. Sometimes it's smarter to do backups manually. I've used Synk in the past and I was very happy with it.

So IMO the OP should think about the amount of data he wants backed up and how he wants to back them up. One forum member (a photographer) uses harddrives for backups. He charges his clients for it and just stores the harddrive. I assume the OP doesn't need all his raw video files instantly available. So instead of `pimping', think about what you want to do, such a solution might actually be faster. Separating your startup/applications drive from your data storage drive is such a way: simultaneous access of both don't interfere with each other.

Sounds like good advice!

I use this one: FoldersSynchronizer - The Official Page and like it allot. I don't
have much experience with lots of different ones though so i have to make too
many assumptions to say it's awesome or anything.

[OreoCookie]

Neither the math nor the argument are flawed.
There has been an extensive study done on the servers of Google regarding harddrive failure. They tried to find correlations between failure rate and stuff like average temperature. All these are factors that can be accounted for in mathematics.
But in your Mac Pro, all harddrives are (roughly) under the same conditions. The fact is that no matter what the probability of failure is (even if you had a way of distinguishing between `good' and `bad' harddrives), the probability that your RAID0 with four drives fails is (approximately) four times as big as the probability of a single drive failing. That's independent of the actual value.

You're right that the probability of failure is just some average over some `good and bad batches', but since you have no way of knowing whether your harddrive is from a batch full of lemons, that's what you have.

The other faulty assumption you make is that these harddrive manufacturers pull these numbers out of a hat. They don't, they have lots of experience and know the average probability of failure of their drives. But again, the former argument is independent of the actual probability itself.

The mathematics is sound (I'm in the process of finishing my PhD in mathematics), trust me on this. This is the way all companies (including harddrive manufacturers) investigate these questions, they base their decisions on statistics.

I would also have a closer look at ninahagen, this member has a lot of experience with RAIDs from a practical perspective, the advice (s)he gives is sound.

[MarkLT1]

Originally Posted by OreoCookie 

This is plainly incorrect. With RAID0, the data is striped across several drives and if one drive fails, you cannot reconstruct any data.

It was 5am when I was typing that out, and reading it again, it wasn't to clear (so I'll fix it). I was comparing the probability of the failure of a RAID0 (~18.5% because you lose all data if one drive fails), to that of 4 separate drives (non RAID0) being 5%^4, or 0.000625%.

As an aside, which field of Mathematics are you getting your PhD in? Getting close to being done? I just finished my PhD up a year ago (Civil Engineering- failure probability in large structures), and I have to say, it feels awesome when you're finally done!

[OreoCookie]

I'm a mathematical physicist. Officially, the name of my department is called `Department of Stochastic Analysis', but it's about mathematical physics mostly. I have a diploma (5-year degree) in physics as well.

Usually I don't go walking around, flashing my titles, though.

[MarkLT1]

Originally Posted by OreoCookie 

I'm a mathematical physicist. Officially, the name of my department is called `Department of Stochastic Analysis', but it's about mathematical physics mostly. I have a diploma (5-year degree) in physics as well.

Sounds pretty tough! I know the math and physics people here had a much rougher grad school experience than I did!

Usually I don't go walking around, flashing my titles, though.

I joke with my wife, that about the only time I'll use my "Dr." title is if our kids end up with some snotty friend.

Best of luck finishing up! Its definitely a tough road, but one that is well worth it in the end.

[Tesselator]

Originally Posted by OreoCookie 

Neither the math nor the argument are not flawed.

I guess we'll have to agree to disagree. But since that sentence actually means both ARE
flawed maybe we can just agree to agree. BTW, if you're interested I could easily tear
that math apart and show you just how flawed it is. It's rather ridiculous when you know
how it's derived and how it's presented.

[OreoCookie]

suki ni shiyou.
Fixed the sentence for ya.

[MarkLT1]

Originally Posted by Tesselator 

I guess we'll have to agree to disagree. But since that sentence actually means both ARE
flawed maybe we can just agree to agree.

Just like you agreed to disagree that a single threaded process can not make use of more than one processor?

No offense, but it sounds like no amount of fact will convince you when you have your mind made up. In this case (and with your earlier claim that a single threaded process can by itself take advantage of multiple processors), your logic is simply wrong, and is not backed up by evidence, nor logic.

[Tesselator]

Originally Posted by MarkLT1 

Just like you agreed to disagree that a single threaded process can not make use of more than one processor?

What does that have to do with this topic? And I guess you had better go reread that thread.
You obviously didn't understand what you read. That is IF you even read it all.

[OreoCookie]

Originally Posted by MarkLT1 

Sounds pretty tough! I know the math and physics people here had a much rougher grad school experience than I did!

I still love it. Here in Germany, only people who are interested study physics and math (as opposed to France, for instance), so I'm in geek town right now

Originally Posted by MarkLT1 

I joke with my wife, that about the only time I'll use my "Dr." title is if our kids end up with some snotty friend.

Yeah, I think it'll be similar with me.
Kids at primary school nicknamed me professor, I hope that's a sign of things to come
Not because I'm in love with the title, but because I would love to be a professional researcher and teacher.

Originally Posted by MarkLT1 

Best of luck finishing up! Its definitely a tough road, but one that is well worth it in the end.

Thanks!

[ninahagen]

Originally Posted by OreoCookie 

Here in Germany...

Where in Germany are you? Which Uni? How is your German? My spouse is Austrian, so I visit Central Europe lots.

[OreoCookie]

Technical University Munich. But I've been to UC Berkeley as a visiting scientist last year for a few months and before that, I've spent a year in Nagoya at Nagoya University (part of me is still in Japan …).
Since I'm in natural sciences, my German (mother tongue) suffers as most of the things I do and think of are in English

[misterdna]

Looks like I found the right thread to ask for advice.

I'm a graphic artist and have been using Macs since the IIci. I currently use the typical CS3 software, and deal with multiple-page projects with working files that at times can be in excess of 20 GB. As an avocation, I do video stuff and use the newest versions of FCP and Motion (which means I can easily start dealing with 50+ GB of data for a project). I have several computers that I use, but am thinking it's time to update my tower to the new Mac Pro. The computer I use the most is a G5 with two internal drives: a 500 GB main drive and a 500 GB scratch drive that I also store old files on. I clone my startup drive regularly to a 500 GB firewire drive, so if anything goes wrong, I have my system, data, and application ready at a moments notice (which is necessary with time-sensitive projects I work on). I'm quite happy with the way this all works.

But now I'm planning on getting a new Mac Pro, and am contemplating the optimum drive set-up for me. I feel behind the curve because I have no experience with RAIDs, and it seems they are necessary to get the best performance when handling a lot of data (as I do). I saw a suggestion of 4 drives set-up as RAID 0+1. But is not having a scratch drive a problem? I also saw solutions with external RAID devices, but does that end up costing more?

I see SierraDragon (who seems really knowledgeable) had this plan in a December post: Apple's RAID card, 750 GB non-RAID main drive, 2x500 RAID 0 for images and scratch, 1 TB non-RAID drive for Time Machine, 1 TB non-RAID external for off site backup

Anyone care to weigh in?

[devastHB]

Hey Guys, sorry haven't been around to reply to all the questions, been busy because I got my Mac Pro yesterday!!!!

I already had the drives in question (4x 500 gig drives), all except the 1TB drive which I had to buy in advance because I wanted to use it to move data. 2 of the 500s were from external enclosures and 2 500s were from my PC. I decided to follow the advice NOT to put the Time machine backup on a JBOD and not raid the boot drive, for fear it may end up useless if i needed to restore from it . Right now my system looks like this:

MAC
internal:
optical (stock) (optical bay1)
320mb (stock boot drive)
1TB RAID 0 (work drive) [2x w/500gig drives]
1TB Drive (time machine backup) (optical bay2)
external:
500 gig connected firewire (bring back and forth to work)
optical drive 2 connected firewire 400

The ono other 500 gig I will place back in my PC which also also has a 600Gig raid5 [3+1 200Gig] (unfortunately this is very old and only supports 250 gig SATA drives)

Anyway, thanks for everyone's advice.

[ninahagen]

Originally Posted by misterdna 

Looks like I found the right thread to ask for advice.

I'm a graphic artist and have been using Macs since the IIci. I currently use the typical CS3 software, and deal with multiple-page projects with working files that at times can be in excess of 20 GB. As an avocation, I do video stuff and use the newest versions of FCP and Motion (which means I can easily start dealing with 50+ GB of data for a project). I have several computers that I use, but am thinking it's time to update my tower to the new Mac Pro. The computer I use the most is a G5 with two internal drives: a 500 GB main drive and a 500 GB scratch drive that I also store old files on. I clone my startup drive regularly to a 500 GB firewire drive, so if anything goes wrong, I have my system, data, and application ready at a moments notice (which is necessary with time-sensitive projects I work on). I'm quite happy with the way this all works.

But now I'm planning on getting a new Mac Pro, and am contemplating the optimum drive set-up for me. I feel behind the curve because I have no experience with RAIDs, and it seems they are necessary to get the best performance when handling a lot of data (as I do). I saw a suggestion of 4 drives set-up as RAID 0+1. But is not having a scratch drive a problem? I also saw solutions with external RAID devices, but does that end up costing more?

I see SierraDragon (who seems really knowledgeable) had this plan in a December post: Apple's RAID card, 750 GB non-RAID main drive, 2x500 RAID 0 for images and scratch, 1 TB non-RAID drive for Time Machine, 1 TB non-RAID external for off site backup

Anyone care to weigh in?

Hi there Mr. dna,

Some observations:

— 16GB of RAM is the minimum for you. I would get 4 x 4GB modules so you can use the other 4 slots if you decide you need them after checking your ins/outs on a typical heavy project. You may well need 32GB.

— You need speed, period. No fussing, no back and forth. Hardcore. Speed. 15k SAS drives are the only thing for you.

— I am making three assumptions based on your post. 1) that you have around 500GB of data, 2) that you are in a relatively slow growth cycle, 3) that your data is critical to you.

— If those assumptions are right, then I suggest the following:

— 5 x SAS drives total (300GB 15k rpm) (4 in the hd bays, 1 in the 2nd optical bay via this PCIe card: Serial Attached SCSI Adapter - ExpressSAS H308 | ATTO Technology). You have to call them to make sure you can boot off it though)

— 1 of the SAS drives dedicated as the system drive (partitioned if you add Windows)

— 1 of the SAS drives as a dedicated as scratch drive.

— 3 of the SAS drives in RAID0 forming a 900GB array, roughly twice your present data.

— for time machine, I would get the Webie RT5e in the 2.5 TB version, and do nightly backups of your RAID0 array, then take it home. It is portable, and your data will be in two places.

— Gotta get the Nvidia GeForce 8800.

Hope that helps.

nina

[misterdna]

Thanks so much for the detailed answer Nina!

Wow, I'm gonna have to let that sink in... Five SAS drives? I hadn't even heard of 'em until I saw they were options for this computer! Time to see what that's going to cost... You didn't mention a RAID card, but I assume I should get the Mac Pro RAID card?

Eek, I don't see deals on 15K SAS drives anywhere -- going this high-end direction instead of settling for something like four 500GB 7200 SATA drives (and no SAS adapter) seems like it will add about $2700 to the price tag. I wish there was a way to know if $2700 extra after the cost of the computer and RAM is worth the speed it will deliver.

Something to ponder, along with the Wiebetech... NinaHagen, you don't fool around!

[ninahagen]

Originally Posted by misterdna 

Thanks so much for the detailed answer Nina!

Wow, I'm gonna have to let that sink in... Five SAS drives? I hadn't even heard of 'em until I saw they were options for this computer! Time to see what that's going to cost... You didn't mention a RAID card, but I assume I should get the Mac Pro RAID card?

Eek, I don't see deals on 15K SAS drives anywhere -- going this high-end direction instead of settling for something like four 500GB 7200 SATA drives (and no SAS adapter) seems like it will add about $2700 to the price tag. I wish there was a way to know if $2700 extra after the cost of the computer and RAM is worth the speed it will deliver.

Something to ponder, along with the Wiebetech... NinaHagen, you don't fool around!

There are deals on the SAS drives, no worries. There are also several to choose from. I will look into it a little and get back to you soon (which models and where to get them).

As to price effectiveness. You are a video editor. That is among the most intensive applications there is, and you will see a speed increase that is literally astounding. The extra outlay should pay for itself in time saved processing. There is a reason Pixar & friends do not use G5 2.0 dual workstations: Speed = $.

If you have a budgetary constraint, you can start with 3 SAS drives (one system, one scratch, one file storage) and 2 x 4GB RAM modules (plus the 2GB stock RAM gives you 10 gigs... a reasonable starting point for a vid edit system). You can add drives and modules in pairs as you go. Add a portable FW800 external drive so you can do a daily backup and take the backup drive off site (or put it in a fireproof safe).

What is your budget like? Could you spend $10k?

PS Yes, I meant the apple RAID card, and you don't need an SAS adaptor... the fit into the drive bays perfectly.

[OreoCookie]

First of all, you don't need an SAS adapter, SAS is backwards compatible to SATA. SAS is the latest version of SCSI. You don't see `deals' on SAS drives, because they are pro-grade drives that aren't sold at Target.

By the way, you don't need five SAS drives, you can mix and match. For instance you can add two 15k drives to make a small, but fast scratch RAID0 volume, one OS X system drive (perhaps also 15k SAS or a 10k Raptor) and two large 7.2k drives for storage. Storage drives don't need to be as fast as scratch drives, pay for the speed where it matters the most.

[misterdna]

Originally Posted by ninahagen 

As to price effectiveness. You are a video editor. That is among the most intensive applications there is, and you will see a speed increase that is literally astounding. The extra outlay should pay for itself in time saved processing.

Actually, I'm a graphic artist professionally, video editing is my avocation (hobby). I figure a fast Mac will help both work and play, but I just want to be clear that my most taxing professional work is using Photoshop and Illustrator. As an amateur video editor, I survive on my current non-RAID, non-SAS equiped Macs, and so I'm not sure the extra cost of the top-of-the-line video editing set-up makes sense for me (since the price tag is soooo hefty). I don't have a specific budget, so it's all up for discussion. But I just want you to have clarity on where I'm coming from.

First of all, you don't need an SAS adapter, SAS is backwards compatible to SATA. SAS is the latest version of SCSI. You don't see `deals' on SAS drives, because they are pro-grade drives that aren't sold at Target.

I am fairly ignorant about SAS (and RAIDs), but I do see that when configuring a Mac Pro, Apple says "SAS drives cannot be used without the Mac Pro RAID card." This gives me a different impression about SAS compatibility than your statement. My assumption of what Nina was saying is the fifth SAS drive will not work with a spare SATA connection in the Mac, and the RAID card only will accommodate 4 SAS drives. Maybe you two experts can argue it out?

I do appreciated the time you've spent answering my questions!

[OreoCookie]

The new Mac Pro has SAS connectors onboard, you don't need the RAID card anymore.

[misterdna]

Originally Posted by OreoCookie 

The new Mac Pro has SAS connectors onboard, you don't need the RAID card anymore.

But do connectors equate to also having the electronics to deal with SAS drives w/o the RAID card? If that's the case, it's bizarre that Apple has the info about the RAID being necessary twice when configuring the Mac Pro with SAS drives. It also says you have to go all SAS or all SATA, which is counter to what you said about being able to mix and match drive types -- is Apple oversimplifying things in an attempt to prevent people from mixing drive types in a RAID configuration?

With RAID card option: "Please note: The Mac Pro RAID Card is required when selecting SAS drives."

With Hard Drive option: "Please note: Mac Pro systems must be configured with either all Serial ATA or all SAS drives. SAS drives cannot be used without the Mac Pro RAID card."

As much as you may be correct, it is hard for me to go against what Apple states clearly without additional references. Can you show me any link that will help me feel more confident in the info you are giving me?

BTW, I'm starting to lean towards going all SATA (to save about $500 per drive), with the possibility of upgrading to SAS in the future. Feeling confident about mixing and matching SAS and SATA drives might change things... Out of curiosity, generally speaking is the jump from non-RAID to a basic RAID more of a speed boost then going from RAID w/ SATA to RAID w/ SAS?

Sigh... The more I learn, the more I realize I don't know. After searching the web for more details on how the new Mac Pros handle mixing of drives, etc., I discovered that a lot of people have similar questions, and almost no one seems to have a definitive answer.

[SierraDragon]

"...this plan in a December post: Apple's RAID card, 750 GB non-RAID main drive, 2x500 RAID 0 for images and scratch, 1 TB non-RAID drive for Time Machine, 1 TB non-RAID external for off site backup..."

That commentary was a "what if" as regarded available configurations of a 2006 Mac Pro. I did a fair amount of homework at Mac Expo but I too: Sigh... The more I learn, the more I realize I don't know.

Today I to am leaning toward all SATA for the same reasons as expressed above. SAS adds a lot of throughput speed but I do not think that I can justfiy the cost. 750 GB non-RAID main drive, 2x1TB RAID 0 array for images and scratch, 1 TB non-RAID drive for onsite backup, very large non-RAID externals for off site backup.

I have filled every hard drive I have ever purchased, so my intent is to start as large as is feasible so drives can stay less than 50% full for as long as possible to avoid the speed reduction that occurs as any drive fills. The RAID 0 drive array in particular will never be allowed to exceed 50% full.

I am thinking about maintaining a clone of the system/apps drive in a FW800 enclosure so I can just remove the backup from the enclosure and replace the main drive if it fails. Is there any reason that would not work?

-Allen Wicks

[Tesselator]

Originally Posted by misterdna 

I saw a suggestion of 4 drives set-up as RAID 0+1. But is not having a scratch drive a problem?

Probably not, no. But 0+1 means almost no performance boost. It'll be about 1.2x for
typical usage. You might be better off not going for a RAID at all in that case. If you
partition your scratch and storage drive in about half the 1st half of that drive (partition 0)
will be close to the same speed as that RAID. Now for a 3 or 4 drive RAID0 (not +1) you
will see a nice boost out of having the raid. A 4-Drive RAID0 will typically deliver speeds
of over 3x (Between 3x and 3.5x).

I also saw solutions with external RAID devices, but does that end up costing more?

Yes lots more but lots more speed too and RAID5 or other advantageous variants! See this
page for a nice overview of the different types: RAID - Wikipedia, the free encyclopedia If you're
not too worried about the money I would go for the hardware RAID (controller).

I see SierraDragon (who seems really knowledgeable) had this plan in a December post: Apple's RAID card, 750 GB non-RAID main drive, 2x500 RAID 0 for images and scratch, 1 TB non-RAID drive for Time Machine, 1 TB non-RAID external for off site backup

Sure. Just remember the more drives you add to a performance enhancing RAID array the
faster the I/O will be.

[Tesselator]

Originally Posted by misterdna 

But do connectors equate to also having the electronics to deal with SAS drives w/o the RAID card?

I didn't read that the new macs have SAS but SCSI is very expensive and I guess it's still
a software RAID so no real advantage (except for people who already invested the thousands
in a SAS array and want to use them in the Mac.)

It also says you have to go all SAS or all SATA,

For sure you will not be allowed to mix and match within a RAID array! You might maybe be
able to have a 3 SAS RAID and an IDE Drive connected at the same time or something like
that. That would be pretty kewl if you could. You could put one 2000RPM drive by itself
for a really fast boot or scratch drive.

With RAID card option: "Please note: The Mac Pro RAID Card is required when selecting SAS drives."

With Hard Drive option: "Please note: Mac Pro systems must be configured with either all Serial ATA or all SAS drives. SAS drives cannot be used without the Mac Pro RAID card."

That sounds correct to me.

BTW, I'm starting to lean towards going all SATA (to save about $500 per drive), with the possibility of upgrading to SAS in the future. Feeling confident about mixing and matching SAS and SATA drives might change things... Out of curiosity, generally speaking is the jump from non-RAID to a basic RAID more of a speed boost then going from RAID w/ SATA to RAID w/ SAS?

I agree about the price! And your question depends on the number of drives, the
spindle speed of the units, and how well the drives you chose behave in a RAID array
and independently.

So, umm, it depends.

Sigh... The more I learn, the more I realize I don't know. After searching the web for more details on how the new Mac Pros handle mixing of drives, etc., I discovered that a lot of people have similar questions, and almost no one seems to have a definitive answer.

If you're near an Apple store walk in and ask at the genius bar - but make sure you press
them for absolute certainty! Those guys often will BS at first if they aren't 100% sure instead
of checking with a tech in the back room - who WILL actually know. Other than that there's
what you're already doing... reading and asking on the forums!

[mduell]

SAS isn't about bandwidth, it's about I/O. SATA drives are just as fast as SAS drives for sequential transfers, but the SAS drives pull ahead for I/O driven tasks.

Originally Posted by OreoCookie 

First of all, you don't need an SAS adapter, SAS is backwards compatible to SATA. SAS is the latest version of SCSI. You don't see `deals' on SAS drives, because they are pro-grade drives that aren't sold at Target.

By the way, you don't need five SAS drives, you can mix and match. For instance you can add two 15k drives to make a small, but fast scratch RAID0 volume, one OS X system drive (perhaps also 15k SAS or a 10k Raptor) and two large 7.2k drives for storage. Storage drives don't need to be as fast as scratch drives, pay for the speed where it matters the most.

Originally Posted by OreoCookie 

The new Mac Pro has SAS connectors onboard, you don't need the RAID card anymore.

SAS uses the same connector as SATA, but the Mac Pro does not support SAS without the RAID card (the Xserve does, since it has a SAS card that can be replaced by a RAID card). You cannot mix SAS and SATA drives on the Mac Pro backplane.