After upgrading from Ispconfig 3.0 to 3.1 odd things started to happen. For example, when saving a DNS secondary zone it would not store the client selected. Same thing when saving an email domian, client info and spam filter setting just would save.
The solution turned out to be simple. Gentlemen – clear your cookies and login again! Problem solved.
On one of my Ubuntu servers I noticed a significant peak in CPU load (load average, LA) and disk I/O about every hour. At first, I suspected that MySQL was the cause of this, doing some houeskeeping or garbage cleaning.
However, it turned out it was caused by the Apache module mod_pagespeed. The high load occuered when pagespeed was cleaning out it’s cache.
The solution was to locate the cache on tmpfs instead. This was done by editing the file /etc/apache2/mods-available/pagespeed.conf and change the location of the cache by the line (/run is located on tmpfs which is RAM memory):
ModPagespeedFileCachePath "/run/cache/mod_pagespeed/"
Then restart Apache by:
service apache2 restart