RAID 0,1, or 5?

[Christopher Grant Harvey]

Hi,

I have had a RAID 0 fail on me.

I have 4 x 500GB sata drives ready to RAID together, I would like to know which option would be best between 0,1, or 5?

I'm leaning towards RAID 5?

Any opinions and experience would be welcome. :usd:

[Christopher Grant Harvey]

OR perhaps RAID 10

" The RAID level where information is striped across a two disk array
for system performance. Each of the drives in the array has a mirror
for fault tolerance. RAID 10 provides the performance benefits of
RAID 0 and the redundancy of RAID 1. However, it requires four hard
drives. "

[Dave Blackham]

Depends what you are trying to do.

http://en.wikipedia.org/wiki/Redunda...tandard_levels

Most likely 5 but whatever you do buy a spare drive in case one fails, same model and type. If its failed due to end of life the others may fail soon too.

[Jeff Kilgroe]

IMO, RAID-5 is a false sense of security. It can save your data if one drive fails, however I have had single drive failures that still result in massive data loss due to other factors surrounding the drive crash.

What is your intended use of this RAID system? What sort of backup system or procedure do you have in place? What sort of system will this be installed on or into? Not all RAID-5 controllers and subsystems are created equal. Crap hardware and/or crap management software can often make it difficult or even impossible to recover from a drive crash, when it should theoretically be possible.

RAID 10 (also known as RAID 0+1) can often be a lot more robust than a single RAID-5 volume.

For smaller arrays -- 5 drives or less, I would be most inclined to use RAID-0 and just be sure I have reliable backups in place. 5 drives or more, I would consider RAID-5, but more likely I would consider RAID-6 as it offers the redundancy of a spare drive already available online in the system. That said, I'm running one Mac pro with all 4 internal drives as a RAID-5 and it performs well. Additional external RAID storage for faster performance / workspace.

[Jonas Rejman]

You could also start using ZFS on a mac or opensolaris. It is a new filesystem, that will become standard in snow leopard, which eliminates the write-hole of RAID5.

Once one grasp, that the controller has to see the drives as JBOD, and that all the parity calculations are done by the filesystem, it gets quite ingenious.
256but checksums on every block.

I have 6 discs in a mac pro here. 1 system and 5 pooled to a raidz2 pool, which equals RAID6. All is done by the FS, of course all the parity takes its toll on the CPU cycles, but even when the mac gets destroyed (e.g. RAID card) - I can mount the drives on another mac, or even opensolaris.

Performance-wise, there are statements that ZFS is as fast as HW raid, because it uses the latest CPU for parity, rather than couple of years old from the controller.

I found it sufficient for uncompressed realtime with quite old 500GB drives in 2K, while having equal to raid6, so I can smash 2 drives at once, and still have the data.

[Christopher Grant Harvey]

Just using the drive for normal video editing. Right now that is HD. I just want a bit of security hence me thinking of moving away from RAID 0 towards other options.

I have a backup plan that is conservative at best, I backup every now and then.

Would a RAID 1 be a better option than RAID 5?

P.S thanks for the feedback.

[michael zaletel]

My recommendation is side-by-side RAID 5's where you mirror the first RAID 5 on the second RAID 5. I personally think this offers the best solution because you can for example take all the drives from the second RAID five and store them off site in a bank safe deposit box for example. Pick them up every week or two and copy any new files over to the mirror.

-shooter

[Christopher Grant Harvey]

I need 4 drives for a R5 right?

[JanneJansson]

Use two sets of raid-0. One you use and another you make manual or rsync copy to. If you make the bakup manually you also can restore the data when it fails, and not depandant upon something/some one else.

Don't use raid 5, unless you have already spent crazy amount of $ on a raid 5 hardware.

[michael zaletel]

Use two sets of raid-0. One you use and another you make manual or rsync copy to. If you make the bakup manually you also can restore the data when it fails, and not depandant upon something/some one else.

Don't use raid 5, unless you have already spent crazy amount of $ on a raid 5 hardware.

This is EXTREMELY dangerous. If ANYTHING goes wrong with even one single drive in either RAID-0 Set during the rsync copy, you will lose everything in both sets.

-shooter