Description of problem:
This is because having it disabled seems to improve performance. This is due to the lock contention by the different epoll threads as well as the fuse thread on the circular buff lock both in the fop call and callback paths.
Just to provide some data - wrt RHHI, I saw an increase in IOPs by 12K with event-history disabled for randrom read workload on Sanjay's setup. So the iops I used to get previously was around 61K. With event-history disabled, iops went up to ~73K.
Moreover this codepath is not unique to RHHI. It should help the other use cases too.
mount -t glusterfs -o event-history=on $HOSTNAME:$VOLNAME $MOUNTPOINT
glusterfs --event-history=on --volfile-server=$HOSTNAME --volfile-id=$VOLNAME $MOUNTPOINT
Version-Release number of selected component (if applicable):
Steps to Reproduce:
The patch and its backports are merged upstream.
Created attachment 1425497 [details]
RHGS 3.4 verification logs
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.