[Gluster-users] Performance optimization tips Gluster 3.3? (small files / directory listings)

[Brian Candler]

On Fri, Jun 08, 2012 at 05:46:42PM +0100, Brian Candler wrote:
> but glusterfs objected to the cache='none' option (possibly this opens the
> file with O_DIRECT?)

Yes that's definitely the problem, as I can see if I strace the kvm process:

stat("/gluster/safe/images/lucidtest/tmpaJqTD9.qcow2", {st_mode=S_IFREG|0644, st_size=774307840, ...}) = 0
open("/gluster/safe/images/lucidtest/tmpaJqTD9.qcow2", O_RDWR|O_DIRECT|O_CLOEXEC) = -1 EINVAL (Invalid argument)

I found http://gluster.org/pipermail/gluster-users/2012-March/009936.html
and tried remounting with '-o direct-io-mode=enable', but that didn't make
a difference.  Also, 'mount' output doesn't show this option anyway.

That page also talked about adding 'option o-direct enable' to the posix
translator, but I'd rather not mess with that directly as I have not yet
found any documentation about how to modify translator options while still
using CLI/glusterd to manage the configuration.

Regards,

Brian.