[ovirt-users] Odd question: changing network MTU
I have an oVirt 4.3 cluster, running in one location. I have to move it
to another location. I've got a couple of 1G links between the sites,
and that's enough bandwidth for this (at least temporarily), but... I
have my iSCSI networks defined with a MTU of 9000, and it turns out the
site-to-site links only allow 1500 (and these links are going away after
this is done, so I don't think either carrier would be interested in
changing things to support larger).
Because of that, the storage won't connect up. I tried going "under the
hood" and setting a firewalld rule to force the MSS to a smaller value,
but that didn't seem to get it.
What happens if I change the MTU of an active iSCSI network in oVirt? I
could just go manually change it on each node's iSCSI interfaces, but
I'm not sure if oVirt might change it back. Also, I'm not sure what
would happen to open iSCSI TCP connections (would they reduce
gracefully).
Any other suggestions/tips/etc.? I'd like to make this as transparent
as possible, so was hoping to live-migrate VMs and storage.
--
Chris Adams <cma(a)cmadams.net>