[Linux-cluster] Is it gfs2 able to perform on a 24TB partition?

[Steven Whitehouse]

Hi,

On Fri, 2014-01-17 at 09:10 -0200, Juan Pablo Lorier wrote:
> Hi,
> 
> I've been using gfs2 on top of a 24 TB lvm volume used as a file server
> for several month now and I see a lot of io related to glock_workqueue
> when there's file transfers. The threads even get to be the top ones in
> read ops in iotop.
> Is that normal? how can I debugg this?
> Regards,
> 

Well the glock_workqueue threads are running the internal state machine
that controls the caching of data. So depending on the workload in
question, yes it is expected that you'll see a fair amount of activity
there.

If the issue is that you are seeing the cache being used inefficiently,
then it maybe possible to improve that by looking at the i/o pattern
generated by the application. There are also other things which can make
a difference, such as setting noatime on the mount.

You don't mention what version of the kernel you are using, but more
recent kernels have better tools (such as tracepoints) which can assist
in debugging this kind of issue,

Steve.