Performance of VM in  DataStore

cgeorgeisaac used Ask the Experts™
We have about 50 VMs in a Specific DataStore (10K) and the performance is very slow only  for One VM.  We use this VM  for running our backup (using CommVault).  Storage IO is not enabled.  Is there any way we can improve the performance for this VM or do we have to add another Datastore (preferably SSD).  Any other advise will be appreciated.
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Hi cgeorgeisaac.

Some more information regarding your actual infrastructure could be helpful.

For example, when you say you have 50 VMs running of a single DataStore, are we talking about a physical raid on the ESXi Host itself? if so, what RAID level is implemented?
If you are running the DataStore as a provisioned part of a larger Storage unit (Like Dell SC4020 For example) what sort of Networking are you using to connect your Host to your Storage Unit? 1 GBPs interfaces? 10 GBPs Interfaces? Optics?

Last but not least, if all Machines are running of the same Store, which in you case is near-line SAS you need to consider the following:
You could be reaching the maximum I/O capacity of your drive Array because you have so many machines running - all machines, even those that are completely idle, constantly use I/O, so much more in a virtual environment, Logs need to be updated, VM logs need to be updated so the hypervisor needs to access the VMDKs and so forth.

If I were you, The first thing I'd do would be to take the backup solution to a different array, for two reasons:
1) if the array suffers a catastrophic failure and the backups were in the same array, that's not really a backup system, is it?
2) Backups requires a lot of I/O, but only at bursts (during backups or restores), while your production environment is always utilizing a lot of I/O, So moving the backup to a different datastrore would help both the backup system and the production system to run faster.
Ajay ChananaMCSE-2003/08|RHCSA| VCP5/6 |vExpert2018
Distinguished Expert 2017
Adding another SSD with definitely help - but you need to consult your storage administrator  that what is more in your environment.

Read or writes ?
Do you have large copy or small copy of file  ?

Based on the above Select the RAID and How much datastore reliability for sustaining any failure. depends on you can choose your final solution.

In short you need to select correct type of RAID and add disk for more performance.

TO know more on Raid follow below.
Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017

Where is the VM suffering in terms of performance, e.g. where is the bottleneck ?

if it is storage, you could look at flash based acceleration products ?

e.g. vFlash
cgeorgeisaacSenior Engineer


Excellent  suggestions.  Our Current storage is on an old  HP Left Hand (10K).  Now shall be working on migrating to new HP 3PAR on SSD and will keep monitoring the performance.    Thanks a ton.

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