thought to be fixed by bug 1114908 but it's not.
Still too much flooding, making any debugging close to impossible, stuff rotates away too quickly, too much noise...
see http://gerrit.ovirt.org/#/c/35837/ for a possible fix
Due to supportability concerns suggesting to block 3.5 release
(checked conf and log file)
# grep 'DEBUG.*::IO' /var/log/vdsm/vdsm.log
Thread-26::DEBUG::2015-01-05 12:31:34,139::__init__::298::IOProcessClient::(_run) Starting IOProcess...
note it does seem to NOT work on upgrade, logger.conf is not being update. so be careful when updating drom intermediate builds (beta included)
usual rpm policy - if logger.conf is pristine (not modified) it would be replaced, if anybody touched logger.conf then the file would be saved on filesystem as logger.conf.rpmnew
but it is not the case and on upgraded systems there is still excessive logging