RAID 5 & Disk Utility

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RAID 5 & Disk Utility

Hello!

I'm new to these forums so forgive me for potentially asking a naive question. I have a complicated disk / storage situation and I'm needing some help resolving it. Basically my setup is as follows:

Externally

I have 3 external LaCie HD's; a 500, 300, and 250. These contain archived design work, photos, movies and music. There is approx. 30 GBs free per HD. They are connected via FW 400. These are not backed up other than on the occasional DVD (I know, I know...).

Internally:

I have the stock Apple drive that is 250 with my working files on there, mostly design work.

I'm hoping to setup a software RAID 5 with Disk Utility across 3 1 TB drives that I recently bought. I have 3 empty internal bays and a friend told me that a RAID 5 would give me 2 TBs of usable space and would mirror my data in case of a failed drive.

My question is, how do I set this up? And, is this a wise solution? Ideally I'd like to have my data be internally stored and backed up.

THANKS in advance! Sorry for the long post.

Jon

Mac Pro Quadcore 2.66 Dual, 12 GB RAM, Mac OS X (10.5.6)

Posted on Apr 21, 2009 12:39 PM

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Answer 1

The hatter

Level 9

61,031 points

Apr 21, 2009 12:48 PM in response to jonaschafer

Disk Utility only does 0 or 1 (mirror) and not RAID5.

You need a hardware controller for RAID5. And I'd go with an external RocketRaid 2314 for $190.

Then I'd move and consolidate your FW400 to something else. And never let a drive get to 10% free space.

While you are at it, I'd invest in a new boot drive as well, WD 640GB Black for instance.

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Answer 2

jonaschafer Author

Level 1

0 points

Apr 21, 2009 1:52 PM in response to The hatter

Is there no way to set up a RAID 5 via software? Is it a bad idea?

I guess I don't understand the mechanics or the pro's of a RAID 5 controller, the HDs are external and connect via SATA cables? That seems to be much more complex than having 3 internal HDs.

My aim is to consolidate the FW400s to my 3 1TB RAID 5 array.

Thanks!

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Answer 3

The hatter

Level 9

61,031 points

Apr 21, 2009 4:00 PM in response to jonaschafer

Why start another thread and go off on another direction?

There are plenty of articles on RAID, how it works. And yes it is more complicated than using 2-3 drives for a stripe or mirror set. My feeling is 3 drives is only RAID3 set at best.

Software can't, there is too much overhead for all the extra overhead and work.

http://en.wikipedia.org/wiki/StandardRAIDlevels

http://www.acnc.com/040101.html

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Answer 4

jonaschafer Author

Level 1

0 points

Apr 21, 2009 4:39 PM in response to The hatter

Whoa....Sorry buddy. You responded so quickly one the first topic so I thought I had been abandoned. Thought I'd see who else was available to talk about this predicament. Easy to understand, really.

Cool, thanks for the articles. I guess I'll look into RAID 3 then...

Who ever thought I'd need a Computer Science degree to back up my data? Humph.

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Answer 5

noice_T

Level 3

545 points

Apr 21, 2009 5:30 PM in response to jonaschafer

If you are just looking to use a raid 3 or 5 for backing up data, I don't think it's worth the trouble. Might as well just partition your 3 x 1TBs, back them up regularly with some backup/clone program, and call it a day~

Unless you need the performance gained from raid 3 or 5 for applications that will actually benefit from it, it might do more harm than it does good.

Raid is not a backup solution, by any means. I've had 2 drives in my 8-drive Raid 5 array, fail within 10 mins of each other, thus destroying the entire raid...All data was lost. Luckily though, I had 2 backups on seperate FW drives.

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Answer 6

The hatter

Level 9

61,031 points

Apr 22, 2009 6:50 AM in response to jonaschafer

You didn't say you want this for backup.

And backup only needs some simple, but duplicate backups sets that you rotate and use on alternate backup sessions.

People with a lot of high value data that changes and being edited sometimes go for RAID6.

If you have a drive that you can't afford to go down or lose (audio recording and editing) you can just have a mirror of 3 drives (I am against the idea of using a mirror and stop at two drives).

Any backup should be external and can be simple Firewire or SATA.
http://discussions.apple.com/thread.jspa?messageID=7479466&#7479466

I don't think you qualify as needing RAID5 so far. Also, get some experience and testing under your belt of what it is and can be done with RAID0 stripe, or RAID1 mirror first.

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