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Hi guys I just got 4 SSDs for my FreeNAS box. This server is only used to serve a single iSCSI extent to my Citrix XenServer pool and was wondering if I should setup them up in a RAIDZ or a RAID 1+0 configuration.

This isn't used for anything in production, just for my test lab so I'm not sure which one is going to be better in this scenario. Will I see a major difference in speed or reliability?

Currently the server has three 500GB Western Digital Blue drives and it's dog slow when I deploy a new version of our software on it, hence the upgrade.

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up vote 3 down vote accepted

I'm not really all that familiar, but this blog here seems like a good writeup.

http://blogs.oracle.com/bonwick/entry/raid_z

Now... the blogger makes the point, you make a tradeoff and its probably speed vs. capacity. Now, he compares RAIDZ to RAID5, but you're comparing it 1+0 which gives you N/2 for capacity. I would assume that RAID-Z gets better recovery performance than RAID5, but still won't outperform RAID10. Since you have SSDs which should be bloody fast... I would go for RAIDZ, but be sure to familiarize myself with the scenarios in which it is degraded or rebuilding before putting into production.

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A little further googling shows that RAIDZ provides dual-parity, which tells me it is N-2 for capacity, and in your case the same as RAID1+0 for capacity. With just four drives I don't know that a software solution is going to outperform a dedicated controller, but it might provide you with some nice flexibility. –  SpacemanSpiff Mar 17 '11 at 0:17
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It can provide single or dual parity; the dual-parity geometry mode is called "raidz2". –  Shane Madden Mar 17 '11 at 0:22

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