Hi Brem El mié, 16-12-2009 a las 20:41 +0100, brem belguebli escribió: > In my multipath setup I use the following : > > polling_interval 3 (checks the storage every 3 seconds) > no_path_retry 5 (will check 5 times the path if failure happens on > it, making it last scsi_timer (/sys/block/sdXX/device/timeout) + 5*3 > secondes ) > > path_grouping_policy multibus (to load-balance accross all paths, > group_by_prio may be recommended with MSA if it is an active/passive > array?) > > >From my experience, > no_path_retry, when using mirror (md or LVM) could be put to fail > instead of 5 in my case. > > Concerning the flush_on_last_del, it just means that for a given LUN, > when there is only one path remaining, if it comes to fail, what > behaviour to adopt. > > Same consideration, if using mirror, just fail. > > The thing to take into account is the interval at which your qdisk > process accesses the qdisk lun, if configured to a high value (let's > imagine every 65 seconds) it'll take (worst case) 60 seconds of scsi > timeout (default) + 12 times default polling interval (30 seconds if > I'm not wrong) + 5 seconds= 425 seconds..... > > Brem > > 2009/12/16 Rafael Micó Miranda <rmicmirregs@xxxxxxxxx>: > -- > Linux-cluster mailing list > Linux-cluster@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/linux-cluster After some testings I have to drop the idea. With both solutions (MDADM RAID software and LVM Mirror) I have some inconsistencies. When a disk of the pair fails sometimes it leaves the qdisk device unreachable. I have tested it with different multipath options (fail_if_no_queue with fail value) and I find the behaviour not predictable. I'm leaving the idea and I'll go back to a 6 nodes + 1 qdisk device architecture. Thanks to all. Cheers, Rafael -- Rafael Micó Miranda -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
