Best Practice Minimum Free Space on Datastore (Prod and No-Prod VMs)

[MrVmware9423]

Dear Team,

I have two datastore on one esx host,Just want to know as a best practice  what will be the % of free space on datastore1 (stored Production VMs also performing backup activity) and Datastore2 (stored non-production VMs no backup activity).

regards

Mr VMware

[SureshKumarMuth]

It depends on many parameters...number if virtual machine etc... check if the following article is helpful for you

VMware KB: Troubleshooting a datastore or VMFS volume that is full or near capacity

[a_p_]

As mentioned before, it depends on several parameters. Once is certainly snapshotting as you already mentioned, another important one is whether the VMs are thin provisioned and the datastore is over-provisioned. The amount of free disk space also depends on disk write activity of the VMs while there are active snapshots. As a rule of thumb you should keep 15-20% free disk space for datastores with either thin provisioned virtual disks or snapshots. The percentage however may vary depending on the size of the datastore.

André

[MrVmware9423]

Thanks Andre & Suresh,

We are using thick provisioned VMs in our environment. Is there any official VMware artical where we can check the same.

The percentage however may vary depending on the size of the datastore.

most of the datastore we have 250GB / 500 GB/ 800 / 1TB size datastore

regards

Mr VMware

[a_p_]

I don't know whether there's an official documentation about how much disk space exactly you should reserve. The vCenter Alert for Datastore Usage is set to 75% (Warning) and 85% (Alarm), so this may be an indicator. However, it really depends on the individual VM's activity and of course the number of snapshots you keep and the time you keep them.

André

[TedH256]

this http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100341...

was I think quoted earlier by a respondent. It gives fairly clear guidelines:

ESX hosts store all files necessary for virtual machine operation in a VMware Virtual Machine File System (VMFS). Proper capacity management is critical because this file system is required for any operations related to a virtual machine. This document outlines potential issues related to a VMFS becoming full.

All VMFS (vmfs2, vmfs3, vmfs5) must retain a level of free space to ensure that the virtual machine functions properly. Ensure that these capacity thresholds are met:

• 200 Megabyte Capacity: VMware suggests 200 MB as the threshold where ESX system administrators take action to resolve capacity issues. VMFS volumes vary widely in size and it is impossible to define a precise percentage, but the risk of unexpected problems become greater at this point.

• 100 Megabyte Remaining: If left unchecked, a VMFS volume grows until only 100 MB of space remains, at which time issues may occur. 100 MB is defined as a critical threshold at which ESX system administrators must take immediate action to correct the issue because VMware VMFS stops growing at this point.

--

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[SureshKumarMuth]

I am not sure about the official document for this but each virtual machine has its own swap file which is going to be created when the VM is powered on which is equivalent to the size of the RAM allocated to VM and swap file is going to use the datastore space... so have atleast 10 -15% free space always to ensure smooth operations and again it depends on the number of virtual machines since all the VMs going to have its own swap file created. Since you have thick provisioned disk, do a calculation for memory overhead and take action accordinly. Hope this will help you. Cheers...

[Gotzu]

On Any datastore there should be 13% free space always. Though this is may not be official but best practice.