SSD disks on vmware

[RicoQQ]

Hey folks

I'm not sure that I am placing this question on the right place, so if not I am sorry and will move it.

Here is the problem. My company has quite a large datawarehouse enviroment. To boost IO we had to do something new. We decided to get hold of som SSD cards. This is cards that you put directly in PCI-E I believe that consists of many SSD disks in Raid, These disks where ment for temp data, if the disks fails there is no problem as we can produce this data quite fast if need be. We are using SAS as a datawarehouse programming language and the rest of our space is allocated on SAN drives. So the actual problem... my technical team tells me that I need to leave 30% of the SSD disk free for vmware to use. What for they do not seem to can tell me but it has something to do with vmware needing to write som files there. Is this really requiered ? 30% of the disk is allot and I have to redesign how to use the rest or buy more. Just to mention it, there is no need for backup or snapshot of these disks, they only consist of temp data for the datawarehouse.

Thanks allot for any reply,

Daniel

[a_p_ · Accepted solution]

Welcome to the Community,

my technical team tells me that I need to leave 30% of the SSD disk free for vmware to use

there might be a rule of thumb to leave 20-30% free disk space on a datastore, but this depends how it is used. In case of thin provisioned disks or snapshots you may need this buffer/space. However it the virtual disks are thick provisioned and no snapshots are needed (not even by your backup application) you can certainly reduce the free disk space to a few GB. Keep in mind that if the VM's base folder is located on this datastore, the VM will create a swap file with size of the provisioned RAM as well as a couple of log files when powered on.

André

[weinstein5]

I agree with Andre's response - there is requirement by vmware  other than the recommendations that Andre suggests

I have also moved to the approriate thread -

[RicoQQ]

Thanx.Just the answere I was hoping for

[Josh26]

Depends heavily on the space too.

On a 100GB LUN I with five VMs, I would consider 30% the minimum to keep free, as 30GB can blow out quite quickly.

On a 5TB LUN, to reserve nearly 1.5TB would seem overkill.

[RicoQQ]

This is a 3 enviroments with 650BG each, so they they take over 500GB total. This makes it so that I have to change my entire disk setup.