[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-users] Network Storage
On Tue, Jan 20, 2009 at 11:53 PM, lists@xxxxxxxxxxxx <lists@xxxxxxxxxxxx> wrote: > Another area of problems is that of using network storage. > > In my case, I'm using legacy 1GB and 2GB fibre channel storage units > connected into fc filers that hand off NFS/CIFS. It's a nice, simple setup > but in trying various combinations, things are still very slow and sluggish. > > I've tried various things such as having an NFS or direct FC share onto each > VM server, then installing the guest onto the network storage. Works fine but > when you start adding servers, things get a bit difficult. The way I see it, when it comes to storage allocation, it's probably best (in terms of balance between performance and managability) to treat xen domUs like any other physical server. You allocate a different LUNs for each domU. Other than giving higher I/O performance, this method has the added benefit that it allows easy converting between domU <-> real servers. > The servers run just fine, nice and fast but, the gotcha so far, seems to be > when copying files across that storage for any of the servers. So for > example, when copying say large backup files, GB sized, that slows down > everything way too much. > Yeah, I know. For a long time we used to centralize every storage on 1 & 2 Gbps FC SAN. This works fine for the most part, until we put I/O-hungry applications on it. Oracle database was competing for I/O with web servers, making performance of both suffer greatly. In the end we find that local storage actually provides MUCH higher I/O throughput, since it has "dedicated" disks with plenty of I/O bandwitdh :p So bottom line, my suggestions are : - treat domU's storage like real server's storage - usual I/O optimizations apply : more disks for more throughput, have lots of available BW, dedicated storage when possible, etc. As a side note, if you're already familiar with FC filers, you might want to try SUN's new Unified Storage or even a simple OpenSolaris-based NAS. You can then use iscsi-exported zfs-volumes which gives you features like : - snapshot and clones (can save space significantly, plus making things like backup a lot easier) - compression (also a space-saver, and might even increase I/O throughput in certain conditions) - chekcsums and raidz to ensure data integrity Regards, Fajar _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
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