среда, 19 октября 2011 г.

PostgreSQL: server closed connection

Today I got a ton of messages

DBI connect('dbname=xxx;host=yyy','username',...) failed: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request. at....

from our network statistic collector.
I spent some time trying to understand what had happened (besides yesterdays power fail). I looked at PostgreSQL server debug log (it honestly told that client just closed connection). There were no traces of dying postgres backend. I rolled back some minor configuration changes which I made yesterday... And later it downed upon me: it was just one old server which was supposed to have its network interface shut down waked after power failure... It was seen in dmesg:

arp: x.y.z.w moved from AA:AA:AA:AA:AA:AA to BB:BB:BB:BB:BB:BB on em0
arp: x.y.z.w moved from BB:BB:BB:BB:BB:BB to AA:AA:AA:AA:AA:AA on em0

Really, power cycling is neccessary sometimes to ascertain that all your services are configured properly :)

вторник, 4 октября 2011 г.

OpenVZ and Java

Today we encountered interesting bug in Proxmox 1.9. Java works in container very slow and randomly fails. There are two possible workarounds: provide at least two CPUs to container or downgrade kernel to 2.6.32-4-pve. I've opted for the first way.