Hi all,

There has been some downtime this morning (about 15 minutes) due to a software update.

I pushed a software update, and immediately servers started crashing according to nagios. Looking at ganglia, it looks like the issue was the familiar issue where scap pushes a few 4-CPU apaches into swap, which then crash and come back a few minutes later. This time, however, obviously a key memcached node fell over, causing a database overload, resulting in the site being mostly inaccessible for about ten minutes.

I prepared to revert the software update, but determined that the problem was not the software update, and a scap would exacerbate the issue. The problem resolved itself spontaneously.

We need to fix things up so the scap script is less liable to push machines into swap :)

-- Andrew Garrett agarrett@wikimedia.org http://werdn.us/