[Gluster-users] question re. current state of art/practice

[Whit Blauvelt]

On Wed, Feb 15, 2012 at 08:22:18PM -0500, Miles Fidelman wrote:

> i.  Is it now reasonable to consider running Gluster and Xen on the same
> boxes, without hitting too much of a performance penalty?

What's in the hardware? What kind of loads are you expecting it to handle?
For a bunch of lightly-to-moderately-used services, I have two modest
servers, each with 2 8-core AMD CPUs and big-but-slow SAS drives in RAID5,
that are running KVM VMs that happen to be each on dedicated DRBD partitions
mirrored across the servers, while the servers are also providing a couple
of Gluster filesystems primarily mounted from elsewhere by NFS. Which is
certifiably insane. Except it works.

I'm sure I would be in serious trouble if any of the services were high
load, or if the demands on the Gluster file systems were greater -
especially in combination with the DRBD traffic. But it's all been very well
behaved. So there are at least some cases where VMs and Gluster (although
note the VMs are not _on_ Gluster in this case) can share hardware without
coming close to melting it down. A lot of cores helps. A situation where
nothing's seriously pounding any of the file systems helps.

And there's a reason I'm not running the VMs on Gluster (yet). I
experimented with that on an older version, and as noted by others it wasn't
suited for it. The newest version is reputed to be far improved, but is only
in beta. In other words having file systems on Gluster that are mounted by
VMs, which are themselves on the same systems but not themselves stored on
Gluster, given not-too-power-hungry stuff, you may be fine. To put the VMs
themselves on Gluster ... probably better to wait until 3.3 is out of beta.

Whit