[NTLUG:Discuss] VMWare server mirror strategy

[Stuart Johnston]

Depending on what type of files you are storing in the tank, you should 
be able to rsync just the files, rather than the full file-system.  In 
this case, you would not need to stop vmware.  It really depends on what 
services you are running and how they access the files.


Daniel Hauck wrote:
> I'm seeking strategy advice.  Here's what I want to do:
> 
> I have two identical machines, each with 1TB (4 x 250MB) with SATA RAID 
> controller.  Each RAID is configured the same with 4 volumes defined 
> (all as RAID5) where 200MB is designated /boot, 2GB is designated 
> {swap}, 10GB is designated / and 700+GB is designated "Tank."  I think 
> the volumes are self explanatory.
> 
> The OS installed is CentOS 5.1 64 bit.  VMWare server 1.05 is installed 
> as well.  A non-gui installation and running mode are active.
> 
> What I'd like to do is keep the "Tank" drives on each machine 
> synchronized.  Ideally, this should be happening at all times.  The two 
> machines will be running VMs and neither will be running both.  What I 
> expect to see is a "cold failover" scenario where, if one machine is 
> having problems or has failed, I can go to the working machine and turn 
> up the remaining machines until I can get his twin brother back online.
> 
> The strategy that sounds most interesting to me is GFS + GNBD.  In this 
> strategy, I would set up some sort of mirrored cluster between the two 
> machines and then share them between each other.  But I have problems 
> with this approach largely because I don't really seem to understand 
> what I'm reading.  I get the general idea but the setup and 
> configuration seems to be so difficult, I get dizzy just trying to read 
> it.  Parts of what I read sounds like it could work and other parts seem 
> to suggest that what I want to do with this will not.
> 
> It has been suggested that "rsync" should be used, but somehow I'm 
> doubting rsync can be used against live, currently in use, files as 
> would be the case with vmware server.  (If it can be done that way, I'd 
> be really glad to learn this since it would seem to be the most simple 
> solution.)  But my guess is that I'd have to set up a job to stop the 
> VMs, then do the rsync, then start them up again.  Not the most ideal 
> solution but certainly easier to wrap my head around.
> 
> Does anyone have anything to offer in this situation?  If GFS is a 
> viable option, might someone offer some steps, tips or even assistance 
> in getting it running?  I'm willing to pay some to make it happen if 
> that's what it takes.  I worry that even if GFS is viable, it might suck 
> too much processing power away from the VMs being hosted though.
> 
> I know I can't be the first person ever to want to do this.  I just 
> can't seem to find much on the web about it.
> 
> 
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