Placing swapfile on NFS server - bad idea?

[carrothospital]

So, I was thinking of putting snapshots onto a NFS server, but I was under the impression that the snapshot files are stored in the same location as the swapfile. I just saw the option to change the swapfile location in the VM client and can choose my Drobo as the location. ESXi and the Drobo are both plugged into a gigabit switch. Would it cause a lot of performance problems when if I changed the swapfile location to a location on the network?

I'm not that worried about changing the location, but was wondering if it's a viable option.

[weinstein5 · Accepted solution]

First off snapshots are stored in the same directory as the VMDK that has the snapshot so moving the swap file will not move the snapshot - yes you can store the swap file on your NAS/NFS datastore with out much problem since it is only used the vmkernel runs out of physical and can not meet the VMs memory requirements - but if this does occur the VM will come to a screeching halt -

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[AlbertWT]

Hm... according to a best practice document that i read somewhere, is it true that by placing Swap file on different LUN than the current VMDK can actually perfroms better ?

cmiiw

Kind Regards,

AWT

[Erik_Zandboer]

Hi,

Often the swapfile is placed on local storage. We have seen mayor issues with swapfiles on NFS. Not so much when just running VMs, but when you start a lot of VMs in parallel (like in a VDI environment) you can get into trouble. As Weinstein states, once the VMs are running you do not want any access to happen to the swapfile in the first place, so you should be allright in an environment where you only run server VMs.

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[weinstein5]

Placing the swapfile on local will prevent vmotion though

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[savantsingh]

If you read Netapp's documentation they suggest to keep all the swapfiles on a seprate datastore.

There is no harm in doing that as long as the datastore is shared to all the hosts in the cluster.... the only draw would be as Erik suggested performance issues if multiple VM's would access the datastore at the same time. This would not happen untill all the VM's restart at the same time or you have a power outage...

Hope this helps!!

[carrothospital]

Thanks everyone for the feedback!