CPU usage issue with Append command (cyrus 3.0.6)

[Ben Carter]

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 at pitt.edu
412-624-6470