Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 27.04.2007 16:50, Vampire D wrote: > We had a DRBD/Heartbeat cluster we were running for a while now using .7 at > the time. > For specific reasons, we broke down the cluster to a single machine by > taking the 2nd one offline. At that point, we are seeing 50% performance > gain in performance. > I was not aware the overhead of DRBD would be that high. > > We were previously using Active/Passive with a single 55G drbd volume on a > 2.4GHz 2GB dual Raptor server with private Gbit drbd repl link and public > 100Mb link with heartbeat on both. > Running a low usage LAMP installation. I have limited knowledge on that topic, just what I observed: - Using 1000HZ kernel timer has positive effects - Jumbo frames are positive for many workloads, not all. OLTP seems not to benefit from it. - Bumping up: net.core.wmem_max net.core.rmem_max net.ipv4.tcp_rmem net.ipv4.tcp_wmem is positive. - A good hardware controller with BBU makes a huge difference. - echo 10 > /proc/sys/vm/dirty_ratio helps if you're running XFS and >= 2.6.20 - In case you have a hardware controller http://www.3ware.com/KB/article.aspx?id=11050 might help -- Regards, H.D.