Swap File on local ESX Host drives, performance issues?

[nhhparker]

Hi All

I am mid way through planning of our virtual environment and my manager has asked if the swap files of the VMs can be put local drives of the ESX host they are on.

We have FC SAN for all our main data, with a one seperate LUN for all VMs and this where the swap file will go if there are issues with storing swap files on the local ESX host.

My main question is does having the swap file on the ESX host effect DRS and Vmotion? I know it slows migration down, this is not a major issue to us, i am more worried about performance of VMs etc.

If their are major performance losses across the platform then I think we can find space for the.

I did find a semi related article but really wanted some more detail if possible, and from any users that would have the same setup.

Many Thanks in advanced

Dan Parker

[belanger74]

Hi,

If you have adequate Shared Storage space, keeping swap files inside Shared Storage can reduce latency and eleminates the need to move swap files during DRS & vMotion.

[athlon_crazy]

I'm more worried when the swap file created actively being used by the VMs. BTW, the swap files only will be created once you power-on the VMs and whether your VMs will actively use it or not, it's depend on how memory hungry your VMs is. Since, you okay with latency during vMotion and DRS, I dont see any major issue to put swap files on the local storage.

vcbMC-1.0.6 Beta

vcbMC-1.0.7 Lite

[bulletprooffool]

Hi and welcome to the community.

Your swap file can live with the VM or on the ESX host.

Hosting ion the ESX host is often recomended (usually when the stoarge for you Vms is a little slow . . like olf NFS storage etc)

You will still be able to vMotion VMs etc if the Swap is on the ESX host, but the vMotion will take longer as the Swap will have to be migrated to the new ESX host, but as stated before this could be beneficial in your environment,

You will only use the vmswp when you oversubscribe memory, so if you have VMs that you'd really like to avoid swapping on,set reservations. vswp is a last resort . . after Balloon driver etc . . the most common instance of high vswp utilisation is when people configure limits on VMs that are far below allocated RAM on the VM.

[nhhparker]

Thanks for the answers guys.

With the moving of the swap file if stored on the ESX host, will this be automated wiht vMotion process? Or will this have to be done manually.

Also if the host dies, so the swap file is not transfered, will there be an issue with starting this VM on another host? (i know on vsphere it creates a new swap file each time start up, just checking)

Thanks

Dan Parker

[bulletprooffool]

If you set the swap to 'on the ESX host' . . it automatically migrates it to the new host as part of vMotion . . eaay