At Mon, 23 May 2011 12:24:22 +0200, Jérémie Tarot wrote: > Hi, > > This is a very interesting scenario... > > 2011/5/23 MORITA Kazutaka <[email protected]> > > > At Sun, 22 May 2011 11:25:44 +0200, > > Gandalf Corvotempesta wrote: > > > 2011/5/21 MORITA Kazutaka <[email protected]> > > > > > > > > The patched version is also available at: > > > > git://sheepdog.git.sourceforge.net/gitroot/sheepdog/qemu iscsi > > > > > > > > See also > > > > > > https://sourceforge.net/apps/trac/sheepdog/wiki/General%20Protocol%20Support > > > > > > > > > If I understand correctly with this patch i'll be able to export a whole > > > sheepdog cluster in a single iSCSI block device and then mount it on a > > > different server that will run the VMs ? > > > Like a distributed SAN, for example: > > > > You can export a Sheepdog volume (not a whole sheepdog cluster) as an > > ISCSI LUN. Please note that the iSCSI support is experimental. I/O > > is not asynchronous (poor performance), and the export configuration > > is not shared among Sheepdog nodes. > > > > > > > > 3 sheepdog node merged in a single cluster and then exported to a single > > > iSCSI device. > > > In front of them, will be 5 debian boxes that mounts the iSCSI device and > > > run VM from it ? > > > > > > If one debian box will die, other 4 will take care of the lost VM by > > running > > > them from the iSCSI devices archieving fault tollerance. > > > > Automatic failover of VMs is not supported. I think it is out of > > scope of the storage system. > > > > > > > > If one sheepdog node will die, other sheepdog will takeover it and move > > the > > > iSCSI target to an available node? > > > > No. You need to start the iSCSI target on the available node, and > > export Sheepdog volumes with the same configuration manually. > > > > In this given setup: > * Can we export the same sheepdog volume from many/all sheepdog cluster > members at the same time ?
Yes. If you run iscsi targets on multiple machines, it should work. > * Can't we use multipathing to connect to the targets to gain fault > tolerance ? Probably, active-standby mode would work, but I haven't tested at all. The restriction of Sheepdog is that one Sheepdog volume cannot be accessed from multiple VMs at the same time. Thanks, Kazutaka -- sheepdog mailing list [email protected] http://lists.wpkg.org/mailman/listinfo/sheepdog
