> James Harper wrote: > >> Hi, > >> > >> I want to configure Director & Storage daemon of Bacula System 3.0.0 on two > >> > >> different nodes (same Linux flavor, CentOS 5.2 to be precise). > > Performance should be the same. I do it on a Xen system where the sd is > > on Dom0 for performance reasons, but the director and the catalog is on > > a DomU for better flexibility (eg snapshot to test an upgrade etc). > > > > > Just curious. What performance problems keep you from running SD in a > domU? I have been experimenting with running SD in a PV domU, but > haven't decided if it makes sense. Not for performance reasons, but > because I have the daemons on a 2-node cluster using heartbeat for > failover. For Dir it works great. For SD, there are issues. SD auto > fails over and maintains the same IP, etc. The primary issue is that > failover still causes a running backup job to fail because the SD-FD TCP > session is broken and the daemons don't attempt to reconnect. Also, > after failing because the TCP session is broken, there is no way > currently to re-run failed jobs. I expect future versions of Bacula will > address those two issues, and Xen 3.4 brings virtual SCSI and SATA > devices to domUs. It will be very convenient to run SD in a domU, even > given the problem that the backup device(s) can only be attached to one > dom0 at a time and may have to be manually moved.
When I first set it up, there wasn't the ability to pass through a SCSI tape drive from Dom0 to DomU so it just plain wouldn't work anyway. If your SD is on DomU, then fd->sd data from an external machine has to: . be received in the Dom0 physical interface . go onto the Dom0 bridge . go onto the Dom0 network backend device for the DomU . go onto the DomU network frontend device . be processed by the sd . go onto the DomU scsi frontend device . go onto the Dom0 scsi backend device . go to the Dom0 physical scsi device Where as if it's on the Dom0, the data only has to: . be received in the Dom0 physcial interface . go onto the Dom0 bridge . be processed by the sd . go to the Dom0 physcial scsi device I have never measured the impact, but there will be one and my guess is that it won't be insignificant. I'll defer to anyone who has actually measured it though :) James ------------------------------------------------------------------------------ The NEW KODAK i700 Series Scanners deliver under ANY circumstances! Your production scanning environment may not be a perfect world - but thanks to Kodak, there's a perfect scanner to get the job done! With the NEW KODAK i700 Series Scanner you'll get full speed at 300 dpi even with all image processing features enabled. http://p.sf.net/sfu/kodak-com _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
