rgny
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ESX Server and Dell 2950

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Looking for some pointers on the best way to get ESX Server running smooth on a Dell 2950

6 SAS 1 TB Drives - Which Raid should be setup Raid 0 or 5 or 1+0 (10)

Also any other tips you can point out.

Thanks

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kjb007
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With 6 drives, I would not want to give up half of my storage. I'd use RAID5, and get the most storage out of my available spindles. ESX will run smoothly on any of the RAID configs, as it doesn't handle the RAID, nor does it care. The difference here is a slight difference in R/W performance between the RAID levels. With a low number of spindles, however, that difference will be almost nil, and not perceptible to any degree. Use RAID5, get the most storage you can, to run a larger number of vm's.

Also, ESX will not recognize individual LUN sizes of greater than 2 TB. Create multiple logical drives in your RAID set to spread your I/O as much as possible. Your VMFS block size will determine how large of a file or vm disk size you can create on that vmfs. 1 MB (default)=256 GB max, 2 MB = 512 GB max, 4 MB = 1 TB, 8 MB = 2 TB max.

-KjB

vExpert/VCP/VCAP vmwise.com / @vmwise -KjB

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kjb007
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With 6 drives, I would not want to give up half of my storage. I'd use RAID5, and get the most storage out of my available spindles. ESX will run smoothly on any of the RAID configs, as it doesn't handle the RAID, nor does it care. The difference here is a slight difference in R/W performance between the RAID levels. With a low number of spindles, however, that difference will be almost nil, and not perceptible to any degree. Use RAID5, get the most storage you can, to run a larger number of vm's.

Also, ESX will not recognize individual LUN sizes of greater than 2 TB. Create multiple logical drives in your RAID set to spread your I/O as much as possible. Your VMFS block size will determine how large of a file or vm disk size you can create on that vmfs. 1 MB (default)=256 GB max, 2 MB = 512 GB max, 4 MB = 1 TB, 8 MB = 2 TB max.

-KjB

vExpert/VCP/VCAP vmwise.com / @vmwise -KjB
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iamxCPx
Enthusiast
Enthusiast

Hi KJB,

What do you mean by:

Create multiple logical

drives in your RAID set to spread your I/O as much as possible. Your

VMFS block size will determine how large of a file or vm disk size you

can create on that vmfs. 1 MB (default)=256 GB max, 2 MB = 512 GB max,

4 MB = 1 TB, 8 MB = 2 TB max.

???

Please advise or give an example. I'm about to deploy RAID-5 on 6 x 146GB Hard Drive on PowerEdge 2950 and would like to know the best way to optimize ESX I/O.

Thanks.

CP

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kjb007
Immortal
Immortal

I/O happens at the disk, or LUN level. If you create a RAID set, your drive protection is extended across drives. When you create a LUN or logical drive within that RAID set, then your LUN is limited to how much I/O it can do, but the I/O limit is per LUN. So, if a host needs to perform some locking, it is doing so at a LUN level, so you spread that operation by providing multiple objects to perform it on.

When you format your drive with VMFS, you have an option of what block size you can use. The block size you choose determines the largest possible filesize on that VMFS. And on VMFS, since your vm's drives are represented as files on a VMFS, that filesize limit effectively becomes your largest possible drive size for that vm on that particular vmfs datastore. The block size -> filesize has already been posted.

With your drives though, I'd create one raid set, and two logical drives. There are controllers that will let you create an array, and then create logical drives within that array. That is what I meant by LUNs. Since your drive sizes are smaller, you may not notice much of a difference between two drives or one.

-KjB

vExpert/VCP/VCAP vmwise.com / @vmwise -KjB
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iamxCPx
Enthusiast
Enthusiast

Thank you sir.

Appreciate the advise. :smileygrin:

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