RAID0 vs. RAID 5

[Avatar_Ang]

I am setting up a test machine for my company. I was wondering, when it comes to VMware whats better.

I have 4x 250GB SATA HDD's. I was trying to find out how big the difference is in performance with 4x HDD's in a RAID0 configuration vs. 4x HDD's in a RAID5. Now I know RAID0 is the fastest, but would I be able to tell the difference if I used RAID5? (just to get some sort of redundancy)

If any one has some insite on this, or reccomenedations, I would greatly appricate it.

Thanks,

[rexchoi]

Flat out, I don't recommend the use RAID0. Especially on SATA.

One drive failure and your whole array is toast along with all your guests. I realize that this may be a test machine without significant data, however, in that case, why is performance a major concern? I'd rather have the reduancy and deal with any performance impact you may have than to have to worry about rebuilding the host and any guests if a drive fails.

I've run multiple VM's on a single RAID5 volume without noticeable performance impact - however, it will obviously depend a lot on what kind of load you will be putting on the array. Exchange/SQL multiple transaction logs with multiple writes will have more of a performance impact on a RAID 5 setup than a low used web server doing mostly reads. If you are really interested in performance, with 4 drives, I would recommend a RAID 10 solution.

[williamarrata]

I'm not sure that RAID0 is the fastest compaired to RAID5. Here is a web link that is kind of the Bible to RAID.

Read the differenced between RAID0 and RAID5 and you'll see that RAID5 is better for your Host.

Hope that helped.

[Phil_White · Accepted solution]

If those are your only two options, then do RAID5 for redundancy. If you're going for pure speed then RAID-0 is your best option. The performance difference in this day and age isn't that great because hard drives are coming with much more cache.

[larstr]

The performance difference in this day and age isn't that great because hard drives are coming with much more cache.

This depends on your workload. In a virtualized environment where you have many virtual machines sharing the same storage devices the performance difference between RAID0 and RAID5 can be quite huge. RAID0 isn't really something you shuold use in a prod environment, but RAID1 and RAID1+0 are also something worth considering as it will give much better performance than RAID5 for certain services (SQL, Exchange, etc).

Lars

[Texiwill]

Hello,

Moved to appropriate forum.

Best regards,

Edward L. Haletky

VMware Communities User Moderator

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Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.

CIO Virtualization Blog: http://www.cio.com/blog/index/topic/168354

As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization