SAN disk speeds?

[Mango96701]

have been told that we should move our VMDK files from the 15k disks to the 10k disks in our SAN array. Will there be any adverse effects doing this to our environment (i.e. vMotion, SvMotioning, etc). Or, will the impact be minimal. The vendor believes we should reserve the 15k disks for other purposes.

[kac2]

ehhh.... performance will be degraded....by how much? i don't know.

i usually always try to put my VMs on 15K drives

[vmroyale]

Hello.

have been told that we should move our VMDK files from the 15k disks to the 10k disks in our SAN array.

Based on what? Did the vendor supply any data or just make the suggestion randomly?

[Mango96701]

don't know... and the new guy in the group but seemed odd to me that the vendor rep (Dell) would advise stepping down on the disk speeds for virtualization. So, the question is: has anyone seen a marked performance hit by using 10K disks in their arrays?

[vmroyale]

It all depends on the workload, that's why I was asking. I have many virtual machines that run excellent on SATA disks. You need to know the workload requirements for your virtual machines, before this question can really be answered. If your workloads are light and don't truly require the 15k disks, then you won't likely notice anything by moving them to the 10k disks. If the workloads absolutely require those 15k disks, then yes you could very well see a performance hit.

Another consideration is the number of disks involved. How many 15k disks do you have and how many 10k disks do you have? It's basically a math exercise, but we need a few more variables to solve it.

[J_Wood]

We have the majority of our production VMware environment running on an HP EVA 8000 with 300GB 10K disk. As long as the server is cared for and configured for performance we have no complaints. We are running virtual SQL and Exchange on that disk subsystem.

[Mango96701]

thanks very much. From what I have been told, Dell has done a survey and discovered that the workloads are generally low and that's why they suggested moving them off the 15K disks in favor of the 10K disks But with the future bringing VMs that include Exchange and SQL....I was concerned.

[vmroyale · Accepted solution]

If Dell did the homework and has data to support the claim, then I see no technical reason to not go with it. As long as you aren't giving up those 15k disks entirely, this move will most likely put you in a better long-term position to support those upcoming Exchange and SQL workloads.

If there is fear of losing the disks entirely, then you might want to hold off or stall a bit while waiting on those bigger workloads. Political battles are different.

[Mango96701]

thanks. I'll go with it