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Eden Aurora May 6, 2013 07:14 PM
Setting up Backup System
I'm thinking of purchasing a Lacie storage backup hard disk. Actually the one i'm looking at has 4-5 hard drive slots.

LaCie 10TB 5big Thunderbolt Series Hard Drive - Apple Store (U.S.)

Question. Can i make 3 of the slots Raid 0 and the other 2 Raid 1 ?
Or do all the slots have to be the same Raid?
 
subego May 7, 2013 11:32 AM
My guess is all the same.

Is the Tbolt a requirement?
 
Eden Aurora May 7, 2013 07:40 PM
Thunderbolt is the fastest data transfer connection, right?
so i would choose that over USB and FIrewire.
 
subego May 8, 2013 09:43 AM
I was thinking Gigabit Ethernet. What do you plan to do put on the drives?
 
OreoCookie May 8, 2013 10:10 PM
Don't create a RAID0 for a backup system! Don't even think about it. It's beyond me why Lacie hasn't seen fit to include RAID5 support.

I'd suggest you have a look at NAS systems instead, ones that support RAID5. For backups, a Gigabit ethernet connection is plenty. Another option would be a Drobo.
 
Waragainstsleep May 9, 2013 04:51 AM
Cheaper gigabit ethernet boxes have cheaper processors and in my experience they tend to be quite slow. I'd go for a Promise Pegasus given the choice. Industrial-grade RAID and thunderbolt speeds.
 
P May 9, 2013 10:50 AM
Quote, Originally Posted by OreoCookie (Post 4229788)
Don't create a RAID0 for a backup system! Don't even think about it. It's beyond me why Lacie hasn't seen fit to include RAID5 support.
Most likely they don't include RAID 0/1 either - OS X supports both in software, as long as they expose each drive to the OS individually.
 
subego May 9, 2013 02:05 PM
Quote, Originally Posted by OreoCookie (Post 4229788)
Don't create a RAID0 for a backup system! Don't even think about it. It's beyond me why Lacie hasn't seen fit to include RAID5 support.

I'd suggest you have a look at NAS systems instead, ones that support RAID5. For backups, a Gigabit ethernet connection is plenty. Another option would be a Drobo.
I think that's why he wants to split it. The RAID 0 wouldn't be for backup, that's the RAID 1.
 
turtle777 May 9, 2013 02:32 PM
Few things:

a) I wouldn't trust Lacie with a RAID system.
b) Don't get a Drobo. They are sloooooowww. Trust me, I have been there.
c) Synology NAS is the way to go.
As far as I understand it, you can configure two HDs as RAID 0 or 1, and the others as RAID 5. Or whatever combination you want / need.

-t
 
P May 9, 2013 02:50 PM
When did you try Drobo? In uderstand they've improved quite a bit the last few years.
 
turtle777 May 9, 2013 05:08 PM
Quote, Originally Posted by P (Post 4229913)
When did you try Drobo? In uderstand they've improved quite a bit the last few years.
Last summer. It was a disaster. And very slow.

I'm so much happier with the Synology.
I should have listened to all those people that advised against Drobos.

-t
 
subego May 9, 2013 06:23 PM
My pair of 1511s are great.

Not the cheapest option though.
 
mduell May 9, 2013 10:13 PM
Quote, Originally Posted by turtle777 (Post 4229948)
Last summer. It was a disaster. And very slow.
The 5N/5D models are no longer so slow. My 5N pushes about 100MB/s over ethernet.
 
Eden Aurora May 13, 2013 07:37 PM
So gigabit ethernet is faster than thunderbolt?
i thought thunderbolt was the latest and greatest in connection speed from Apple.
 
OreoCookie May 13, 2013 08:53 PM
Gigabit Ethernet is slower, but given what you want, a storage bin for backups, you don't need the highest theoretically possible throughput. Moreover, all multidisk setups need some internal logic which slows down some operations but offers you larger contiguous disk space.

Don't worry so much about connection speed. What you really want is RAID5/6 capabilities (or something analogously). RAID5 takes N hard drives and gives you the capacity of N-1 hard drives, the remaining hard drive protects you against hard drive failure (if one of the drives dies, your data is safe). RAID6 is the same as RAID5, it protects against the failure of 2 drives (at the expense of capacity).

The other option is that you take a PC and install FreeNAS on it.
 
shifuimam May 16, 2013 12:08 PM
It may or may not be worth mentioning here that RAID 5 is for minimizing downtime in the event of a hard drive failure. It also allows you to increase the total available space on a single volume, since it spans multiple physical hard drives. It is not a method of keeping the data on the RAID backed up. You could do something like RAID 5+1, which is mirroring the RAID 5 array, or even something simpler - just RAID 1, which allows you to keep two hard drives mirrored between each other.

I have seen Mac users with a dead computer drive and, unfortunately, a dead Time Machine drive at the same time. If you end up in that situation, you're boned. If you're using a RAID 5 array as your backup, you will generally be okay (it's unlikely multiple drives will fail simultaneously in your RAID), but for your absolutely most critical files (especially things like photos and documents that you can't just re-download if you lose them), I'd highly recommend looking at a secondary cloud-based solution like Box.net or Dropbox or Skydrive.

Also: if you decide to make a home NAS, do not waste your money on a physical RAID controller. Use the software RAID capabilities of whatever OS you choose (both Windows Server 2008 and Linux, as well as FreeNAS, have built-in software RAID support).
 
mduell May 16, 2013 01:35 PM
Quote, Originally Posted by shifuimam (Post 4230825)
It may or may not be worth mentioning here that RAID 5 is for minimizing downtime in the event of a hard drive failure. It also allows you to increase the total available space on a single volume, since it spans multiple physical hard drives. It is not a method of keeping the data on the RAID backed up. You could do something like RAID 5+1, which is mirroring the RAID 5 array, or even something simpler - just RAID 1, which allows you to keep two hard drives mirrored between each other.
1) Many RAID5 systems allow you to continue to access data while rebuilding, so there is no downtime.

2) RAID 1 is also not a backup, layered with RAID5 or otherwise.
 
shifuimam May 16, 2013 04:17 PM
I was referring more to the fact that RAID 1 involves duplicate copies of your data. RAID 5 doesn't. If your RAID 5 goes kaput for any reason, there's no other copy of your data to fall back on.
 
mduell May 17, 2013 01:12 AM
If your RAID1 array goes kaput (controller malfunction or whatever), you also have zero copies of your data.
 
besson3c May 17, 2013 04:24 AM
Quote, Originally Posted by shifuimam (Post 4230825)
Also: if you decide to make a home NAS, do not waste your money on a physical RAID controller. Use the software RAID capabilities of whatever OS you choose (both Windows Server 2008 and Linux, as well as FreeNAS, have built-in software RAID support).
For RAID-5 using software RAID is a very bad idea because of the RAID-5 write hole.
 
P May 17, 2013 07:59 AM
Quote, Originally Posted by mduell (Post 4230956)
If your RAID1 array goes kaput (controller malfunction or whatever), you also have zero copies of your data.
If the controller craps out, can't you just use either drive as a regular HD to recover your data?

Quote, Originally Posted by besson3c (Post 4230960)
For RAID-5 using software RAID is a very bad idea because of the RAID-5 write hole.
Rather say that a software RAID5 setup should include a UPS.

(I'm surprised you didn't take the chance to push RAID-Z again?)
 
besson3c May 17, 2013 03:16 PM
Quote, Originally Posted by P (Post 4230981)
If the controller grease out, can't you just use either drive as a regular HD to recover your data?
I think the trick would be mounting a RAID member individually rather than as the single RAID device node. The individual device nodes probably don't have a partition map that can be used, but perhaps you could create this partition map with something like gparted? I've never actually tried this myself, just thinking out loud here.


Quote
Rather say that a software RAID5 setup should include a UPS.

(I'm surprised you didn't take the chance to push RAID-Z again?)

A UPS would probably work too, although if left unattended during a power outage and your OS was still alive and your machine was still writing stuff when the UPS ran out of power there could be loss. I think the idea of a RAID-5 card battery is that the battery will kick in when the rest of the machine has been powered off and the OS is not running.

I'm kind of writing off ZFS at this point. The Oracle thing just seems to dodgy to me for this to have a future, and I haven't heard any recent reports about Zevo and its success/failure rates, company success, future plans, etc. I suspect that ZFS is sadly technology that may ultimately fall by the wayside. Perhaps ZFS doesn't need active maintenance, but perceptions of its extinction would scare me off a little.
 
mduell May 17, 2013 06:34 PM
Quote, Originally Posted by P (Post 4230981)
If the controller craps out, can't you just use either drive as a regular HD to recover your data?
Note I was talking about a controller malfunctioning rather than ceasing to function.

In the case it ceases to function, you may be able to mount one drive on its own, but I don't know if that's always the case.
 
P May 18, 2013 10:52 AM
Quote, Originally Posted by besson3c (Post 4231053)
I think the trick would be mounting a RAID member individually rather than as the single RAID device node. The individual device nodes probably don't have a partition map that can be used, but perhaps you could create this partition map with something like gparted? I've never actually tried this myself, just thinking out loud here.
Why would the partition map not be replicated? The in RAID 1, the RAID controller's job is to send all writes to two drives - it shouldn't understand what is the partition map and what is your files.

If the controller is flaky and fails to do that, as mduell suggests, then either drive might not have all the data it needs, but if the controller dies cleanly, it ought to work.

Quote, Originally Posted by besson3c (Post 4231053)
A UPS would probably work too, although if left unattended during a power outage and your OS was still alive and your machine was still writing stuff when the UPS ran out of power there could be loss. I think the idea of a RAID-5 card battery is that the battery will kick in when the rest of the machine has been powered off and the OS is not running.
Normally the UPS will send a command to the server to shut down cleanly if power is running out.
 
shifuimam May 18, 2013 09:27 PM
Without re-quoting a bunch of posts...

Get a cheap UPS to avoid any possible issues with your server shutting off in the middle of writing data to the RAID. The odds of this happening for a home user are pretty slim to begin with.

A hardware RAID controller has the distinct disadvantage of being (a) very expensive for home users and (b) completely proprietary. If your RAID card craps out, even six years down the line, the only way to access the data on the RAID is to get another identical RAID card. With software RAID, all you need is the same software support - put the drives in another machine, install the same OS (I was able to even go from Server 2003 to Server 2008 R2), and you can get to your data pretty quickly and painlessly.

For the record, the RAID controllers found on pretty much any non-OEM commodity motherboard these days are crap. They're bastardized software RAIDs that don't offer any real performance value over using a straight up software RAID.

I've been using software RAID 5 in Windows Server since about 2007 (and didn't get a UPS until much later) and have not ever run into issues. I just don't think the expense and headache of a hardware RAID controller is justified for a home user who simply wants a file server for backing up their stuff.
 
besson3c May 18, 2013 11:07 PM
Quote, Originally Posted by P (Post 4231114)
Why would the partition map not be replicated? The in RAID 1, the RAID controller's job is to send all writes to two drives - it shouldn't understand what is the partition map and what is your files.

If the controller is flaky and fails to do that, as mduell suggests, then either drive might not have all the data it needs, but if the controller dies cleanly, it ought to work.
I guess I'm coming at this from a Linux perspective, where the partition type used for RAID is different than your standard partition map. I'm not sure what OS X does.

Quote
Normally the UPS will send a command to the server to shut down cleanly if power is running out.
Ahh, I didn't know that!
 
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