For starters:
strace one of the processes & see if it's making any system calls at all.
pstack a process multiple times to get PC samples.
gcore a process to get a core dump & take a look at the core dump with gdb.
If you know that a specific account is likely to have this issue, enable
IMAP protocol logging for the account. This may tell you something.
Ben
On 05/08/2018 02:04 PM, Andrew Nichols via Info-cyrus wrote:
Hello,
We've recently upgrade to cyrus 3.0.6 and we've been experiencing issue
where imapd will get stuck in an Append and take 100% CPU time. The
client doesn't see anything weird. I've tried leaving the processes to
see if they resolve, but they never did. Doing a kill -TERM twice will
kill the process. I did not notice any issues with cyrus 3.0.5, but
we've been trying to get Xapian indexing going, so we moved to 3.0.6.
Does anyone have any information on where I can look to rectify this issue?
Here's an example of the ps output:
87556 cyrus 1 102 0 163M 24192K CPU7 7 1:56 96.71% imapd: imap: <client
hostname> [<clientip>] <username> user.<username>.<folder1> Append (imapd)
89680 cyrus 1 102 0 163M 24280K CPU4 4 3:10 96.22% imapd: imap: <client
hostname> [<clientip>] <username> user.<username>.<folder2> Append (imapd)
43932 cyrus 1 102 0 161M 23416K CPU5 5 1:41 96.17% imapd: imap: <client
hostname> [<clientip>] <username> user.<username>.<folder3> Append (imapd)
81590 cyrus 1 102 0 163M 24976K CPU6 6 3:14 94.76% imapd: imap: <client
hostname> [<clientip>] <username> user.<username>.<folder4> Append (imapd)
--
Ben Carter
University of Pittsburgh/CSSD
Network Operations Center
bhc@xxxxxxxx
412-624-6470
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