[Gluster-users] Gluster v 3.3 with KVM and High Availability

Mark Nipper nipsy at bitgnome.net
Thu Jul 12 08:40:14 UTC 2012

On 12 Jul 2012, Brian Candler wrote:
> And I forgot to add: since a KVM VM is a userland process anyway, I'd expect
> a big performance gain when KVM gets the ability to talk to libglusterfs to
> send its disk I/O directly, without going through a kernel mount (and hence
> bypassing the kernel cache). It looks like this is being developed now:
> http://lists.gnu.org/archive/html/qemu-devel/2012-06/msg01745.html
> You can see the performance figures at the bottom of that post.

	Something concerns me about those performance figures.
If I'm reading them correctly, the normal fuse mount performance
is about what I was seeing, 2-3MB.  And now bypassing everything,
libglusterfs is still capping out a little under 20MB/s.

	So am I kidding myself that approaching 45-50MB/s with a
FUSE based Gluster mount and using cache=writethrough is actually
a safe thing to do really?  I know the performance is abysmal
without setting the cache mode, but is using writethrough really
safe, or is it a recipe for disaster waiting to happen?

Mark Nipper
nipsy at bitgnome.net (XMPP)
+1 979 575 3193
I cannot tolerate intolerant people.

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