Re: [ovirt-users] oVirt Instability with Dell Compellent via iSCSI/Multipath

> Another issue may be that the setting for COMPELNT/Compellent Vol are wrong; > the setting we ship is missing lot of settings that exists in the builtin > setting, and this may have bad effect. If your devices match this , I would > try this multipath configuration, instead of the one vdsm configures. > > device { > vendor "COMPELNT" > product "Compellent Vol" > path_grouping_policy "multibus" > path_checker "tur" > features "0" > hardware_handler "0" > prio "const" > failback "immediate" > rr_weight "uniform" > no_path_retry fail > } I wish I could. We're using the CentOS 7 ovirt-node-iso. The multipath.conf is less than ideal

instantly overwrites it. To be clear, yes I know changes do not survive reboots and yes I know about persist, but it changes it while running. Live! Persist won't help there. I also tried building a CentOS 7 "thick client" where I set up CentOS 7 first, added the oVirt repo, then let the engine provision it. Same problem with multipath.conf being overwritten with the default oVirt setup. So I tried to be slick about it. I made the multipath.conf immutable. That prevented the engine from being able to activate the node. It would fail on a vds command that gets the nodes capabilities and part of what it does is reads then overwrites multipath.conf. How do I safely update multipath.conf?

> > To verify that your devices match this, you can check the devices vendor and procut > strings in the output of "multipath -ll". I would like to see the output of this > command. multipath -ll (default setup) can be seen here. http://paste.linux-help.org/view/430c7538 > Another platform issue is bad default SCSI node.session.timeo.replacement_timeout > value, which is set to 120 seconds. This setting mean that the SCSI layer will > wait 120 seconds for io to complete on one path, before failing the io request. > So you may have one bad path, causing 120 second delay, while you could complete > the request using another path. > > Multipath is trying to set this value to 5 seconds, but this value is reverting > to the default 120 seconds after a device has trouble. There is an open bug about > this which we hope to get fixed in the rhel/centos 7.2. > https://bugzilla.redhat.com/1139038 > > This issue together with "no_path_retry queue" is a very bad mix for ovirt. > > You can fix this timeout by setting: > > # /etc/iscsi/iscsid.conf > node.session.timeo.replacement_timeout = 5 I'll see if that's possible with persist. Will this change survive node upgrades? Thanks for the reply and the suggestions. _______________________________________________ Users mailing list Users(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/users