503 errors with php 7.4 fpm

Hello,

We are using Omeka Classic 7.0. My system admin upgraded php to php 7.4 fpm and since then we have been getting 503 errors when saving records. The errors in the log are:

WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 16 children, there are 9 idle, and 77 total childrentype 

My system admin has quadrupled the relevant pm.* levels, but we are still having issues. any advice?

Jen Cwiok
Systems Librarian
AMNH Research Library

Omeka 2.7 isn’t totally compatible with PHP 7.4: the just-released 2.7.1 is, though. I’m not totally sure that’s what your problem is but it’s a decent thing to start with.

Totally helpful start. I’ll upgrade today and see if that helps. Appreciate the quick response, John!

Hi John,

I upgraded to 2.7.1 and restarted fpm and httpd, but I’m still getting the errors. Saving records results in a 503 error and when I check the log at php74/log/php-fpm/error.log, I immediately see the following after I try to update a record. Do you think we have to install an earlier version of php?

[03-Feb-2020 13:34:17] NOTICE: Terminating …

[03-Feb-2020 13:34:18] NOTICE: exiting, bye-bye!

[03-Feb-2020 13:34:18] NOTICE: fpm is running, pid 15650

[03-Feb-2020 13:34:18] NOTICE: ready to handle connections

[03-Feb-2020 13:34:18] NOTICE: systemd monitor interval set to 10000ms

[03-Feb-2020 13:38:34] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 19 idle, and 31 total children

[03-Feb-2020 13:38:43] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 19 idle, and 43 total children

[03-Feb-2020 13:38:44] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 16 children, there are 19 idle, and 44 total children

[03-Feb-2020 13:38:45] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 19 idle, and 45 total children

[03-Feb-2020 13:38:46] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 17 idle, and 46 total children

There shouldn’t be a problem in general running Omeka 2.7.1 on PHP 7.4. I have personal experience with that combination and using FPM and haven’t encountered this kind of problem.

The “seems busy” warnings are odd… I’m not really sure what’s going on there to cause so many clients so quickly. Do other things not cause these errors, like just viewing pages?

One thing to check: this looks like it’s just the error log for the PHP FPM server itself. You should have another log that’s for the actual “pool” being used, a log where more useful error messages might appear. Or you could check the system-wide logs for some possible information, like is PHP crashing?