VM Volumes under iocage?

[The Presence]

Is there a benefit or negative consequence to have your VM volumes under the iocage filesystem? I realize that iocage is for jails, but should the vm volumes be elsewhere?

 

[Patrick M. Hausen]

There are no technically negative consequences as far as I know but from a management point of view wouldn't it be preferable to have different things in separate places?

Things to consider:

• pool topology - do you have more than one pool? VMs definitely profit from SSDs and/or mirrored vdevs instead of RAIDZ
• cache/sync policy - you might want so set sync=always for VMs, if your underlying device is fast enough
• snapshot/replication policy - you might want to have different frequency and/or retention for VMs and jails

Datasets are "dirt cheap" in ZFS, you can easily have hundreds of them. I use e.g. mypool/vm/vmname-disk0 for my zvols.

 

[The Presence]

You make a very good point. I do have a few SSDs that I could install and not add to the zraid, and put at least the boot volumes for those VMs on those devices instead.

Now to find the easy way to migrate...
Create a snapshot
zfs send
change pool contents
remove disks from vm
zfs receive
add disks back to vm
maybe?

 

[Patrick M. Hausen]

• shutdown VM
• create snapshot
• zfs send oldpool/path/to/zvol@snapshot | zfs receive newpool/path/to/newzvol
• zfs destroy newpool/path/to/newzvol@snapshot # just removes the snapshot, not the zvol
• edit disk device, change zvol, save
• boot VM
• if all is well zfs destroy -r oldpool/path/to/zvol

 

[The Presence]

Looks great. Thanks for your help. I'll throw the SSDs in tomorrow and try it out.

 

[The Presence]

Looks like its a success. Boot volumes are on SSD, with a data drive outside of the iocage on ZRAID. Initially, for some reason, VNC did not work, but rebooting the system fixed that. No IP change on the NAS *shrug*.

Thanks for the help. This is way more reasonable.