I have the following situation: I have a home server running debian stable that handles my emails. It is a getmei/postfix/courier combination. On my desktop PC I use debian stable with kde and as mail client kmail/kontact (as imap(s) client). The server stores the mails of several mailing lists, so there are quite a lot of mails in my mail folder (maildir format).
Some days ago I noticed that kmail takes a long time to get the content of a folder on the imap server. Even after 15 min there was no result there. On looking on the server CPU, I found that the CPU load is at approx. 50% for some minutes and the hd is working quite hard (Acoustically and via iotop).
The result is, that I cannot access some folders on the imap server anymore. These folders are nearly empty! That means this cannot be a problem of dozens of mails in this folder.
After some time (2 or 3 min) the cpu load drops but kmail still waits for the results from the server. Normally I have to manually break kmail vis SIGTERM as it hangs now and then as this happens.
Now I do not know why courier has this high load and why it does not answer the kmail query correctly.
What can I do to
- get the reason for the high load?
- solve the problem?