Oops. I missed the note when I went through the core. Sorry everyone for the incorrect information I provided earlier about libgfapi. And thank you Niels for bringing up the correct information.
Regarding libvirt parsing the provided XML; according to a table provided under [1], a source of type `gluster` can have only one host. So it seems, libvirt doesn't support backup volfile servers. I haven't been able to find any information on qemu's support, so I'm assuming it doesn't support backup volfile servers either. ~kaushal [1]: https://libvirt.org/formatdomain.html#elementsDisks On Wed, Jan 28, 2015 at 3:11 PM, Niels de Vos <[email protected]> wrote: > On Wed, Jan 28, 2015 at 02:06:32PM +0530, Pranith Kumar Karampuri wrote: > > Added Niels and Shyam who may know about this. > > > > Pranith > > On 01/27/2015 12:25 PM, Arash Shams wrote: > > > > > >is there anyone pay attention to my question ? > > >------------------------------------------------------------------------ > > >From: [email protected] > > >To: [email protected] > > >Date: Sun, 25 Jan 2015 08:16:49 +0000 > > >Subject: [Gluster-users] how to Set BackupVol for Libgfapi ?? > > > > > >Hello > > >is this possible ?? > > > <disk type='network' device='disk'> > > > <driver name='qemu' type='qcow2' cache='none'/> > > > <source protocol='gluster' > name='vol1/vms/disks/cmsrm-ui01.qcow2'> > > > <host name='141.108.36.19' port='24007'/> > > > <host name='141.108.36.20' port='24007'/> > > > <host name='141.108.36.21' port='24007'/> > > > <host name='141.108.36.22' port='24007'/> > > > </source> > > > <target dev='vda' bus='virtio'/> > > > <address type='pci' domain='0x0000' bus='0x00' slot='0x05' > > >function='0x0'/> > > > </disk> > > >so when one server goes down my vm dont goes down !!! > > This is intepreted by libvirt, and I do not know if the syntax is valid > or how libvirt does this. > > libgfapi offers this functionality by calling glfs_set_volfile_server() > a number of times with different servernames/addresses: > > https://github.com/gluster/glusterfs/blob/master/api/src/glfs.h#L134 > > Note that the specified server is only a single-point-of-failure when > the initial connection to the volume is made. Most users seem to use > round-robin-DNS or a virtual IP-address (with some HA/failover solution) > to prevent this SPOF. > > After connecting, the client knows about all the servers that are part > of the volume. If one server goes down, others will be used > automatically. > > If one brick of a replica goes down, there will be a timeout (by default > 42 seconds) until an other brick is tried. Depending on the > configuration of the storage inside the VM, you could run into read-only > filesystems whan such a failover happens. > > From the Gluster side, you could try tuning the network.ping-timeout > option. Or inside the VM you can set a SCSI-timeout per disk (in a sysfs > file like /sys/block/sda/device/timeout), you'll need a udev-rule or > something to make the change premanent. > > HTH, > Niels > > _______________________________________________ > Gluster-users mailing list > [email protected] > http://www.gluster.org/mailman/listinfo/gluster-users >
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