Configure addition HDD on VMware server

My current VMware has 4 HDD running in RAID-5, with one datastore on the VM server.

I will add 4 more HDD to the server. Just wonder whether there is any difference in performance if

1. configure 4 new HDDs with separate RAID5 with a new datastore
2. extend the current RAID with "4 HDDs"  and extended the size of the existing datastore.

Any comment ? Tks
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Scott GorcesterCTOCommented:
I don't think you will have a noticeable difference in performance. If you are going to add the drives to the existing RAID 5 make certain that the speed of the drives is identical. Also the drives cannot be smaller in capacity and if they are larger capacity the extra space will not be accessible. Adding drives to the array may improve the performance of the array due to having more spindles.

#Edited By

Andrew Hancock
VMware Zone Advisor
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
More Spindles = More Disks = More Performance = More IOPS.

So yes, the more spindles in a RAID set, will give your VMs more IOPS.

Some Rough calculations...

RAID with 4 Disks

RAID 5 4 x 600 SAS 15k Drives - Approx 200 IOPS each disk. assuming 33% writes

Total IOPS = (200 IOPS x 4 disks)/(0.67+4*.33))
           = 402 IOPS

RAID with 8 Disks

RAID 5 8 x 600 SAS 15k Drives - Approx 200 IOPS each disk. assuming 33% writes

Total IOPS = (200 IOPS x 8 disks)/(0.67+4*.33))
           = 804 IOPS

So a difference of 400 IOPS, e.g. DOUBLE the IOPS!

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Scott GorcesterCTOCommented:
ok ty
AXISHKAuthor Commented:
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.