Re: [ovirt-users] What recovers a VM from pause?

Hello, We're planning a move from our old building towards a new one a few meters away. In a similar way of Martijn (https://www.mail-archive.com/users@ovirt.org/msg33182.html), I have maintenance planed on our storage side. Say an oVirt DC is using a SAN's LUN via iSCSI (Equallogic). This SAN allows me to setup block replication between two SANs, seen by oVirt as one (Dell is naming it SyncRep). Then switch all the iSCSI accesses to the replicated LUN. When doing this, the iSCSI stack of each oVirt host notices the de-connection, tries to reconnect, and succeeds. Amongst our hosts, this happens between 4 and 15 seconds. When this happens fast enough, oVirt engine and the VMs don't even notice, and they keep running happily. When this takes more than 4 seconds, there are 2 cases : 1 - The hosts and/or oVirt and/or the SPM (I actually don't know) notices that there is a storage failure, and pauses the VMs. When the iSCSI stack reconnects, the VMs are automatically recovered from pause, and this all takes less than 30 seconds. That is very acceptable for us, as this action is extremely rare. 2 - Same storage failure, VMs paused, and some VMs stay in pause mode forever. Manual "run" action is mandatory. When done, everything recovers correctly. This is also quite acceptable, but here come my questions : My questions : (!) - *WHAT* process or piece of code or what oVirt parts is responsible for deciding when to UN-pause a VM, and at what conditions? That would help me to understand why some cases are working even more smoothly than others. - Are there related timeouts I could play with in engine-config options? - [a bit off-topic] Is it safe to increase some iSCSI timeouts of buffer-sizes in the hope this kind of disconnection would get un-noticed?