[CentOS] 6.2 kernel issues

Tue Mar 13 15:23:11 UTC 2012
m.roth at 5-cent.us <m.roth at 5-cent.us>

A couple weeks ago, after we moved a user's home directory from a 5.7 box
to 6.2, he came to complain about slowness.

Unpack file from NFS-mounted directory to local disk, like /tmp,
everything's normal. cd to the NFS-mounted directory, and unpack it there,
and it was six to seven times slower. We repeated this a number of times,
on a number of machines. At first, we thought it was an NFSv4 issue, and I
filed a bug with RedHat about it.

Then we did more testing; it seems to occur with 6.2; it's going to happen
if that's got ext4.

However, my manager saw something else, just today: he noticed one of our
nightly backup servers was taking much, much longer to complete the rsync
and delete. Then he saw that I'd updated that backup server to 6.2, and
after the backups started running again (probably missing modules), they
were taking a lot longer... about 6-7 times longer. As in going from
between .5 and 1 hr, to 5.5 to 9 hours.

Anyone else seeing this behavior?