APC file cache not working properly getting internal server error 500

Question

I am having some problem with APC working properly. File cache always shows Hits = 1 and misses keep increasing, but at the same time, the cached file entries show some numbers in hundreds over some time. User cache entries shows to be working normally it seems. But almost twice a day i keep getting Internal server error and then have to restart php-fpm. I hv allocated 1024M memory and some other regular config stuff. If you have more idea, can i have your email ID to discuss this and send you more details about it.

The APC config is as following. I have tried Non-zero ttls and other options. Also, in the FastCGI config - I have tried settingPHP_FCGI_CHILDREN as '0' and other values. I have set PHP_FCGI_MAX_REQUESTS (12000) more than FcgidMaxRequestsPerProcess value (8000), as i found in this article, http://httpd.apache.org/mod_fcgid/mod/mod_fcgid.html

But still internal server error keeps coming almost twice a day and I have to restart PHP-FPM

APC config as below:

apc.cache_by_default 1 apc.canonicalize 1 apc.coredump_unmap 0 apc.enable_cli 0 apc.enabled 1 apc.file_md5 0 apc.file_update_protection 2 apc.filters apc.gc_ttl 3600 apc.include_once_override 1 apc.lazy_classes 00 apc.lazy_functions 0 apc.max_file_size 4M apc.mmap_file_mask /tmp/apc.mXJeFR apc.num_files_hint 10000 apc.preload_path apc.report_autofilter 0 apc.rfc1867 0 apc.rfc1867_freq 0 apc.rfc1867_name APC_UPLOAD_PROGRESS apc.rfc1867_prefix upload_ apc.rfc1867_ttl 3600 apc.serializer default apc.shm_segments 1 apc.shm_size 1024M apc.shm_strings_buffer 4M apc.slam_defense 1 apc.stat 1 apc.stat_ctime 0 apc.ttl 0 apc.use_request_time 1 apc.user_entries_hint 4096 apc.user_ttl 0 apc.write_lock 1 

PHP.FastCGI config is as following:

#!/bin/bash PHPRC="/etc/php.ini" PHP_FCGI_CHILDREN=16 PHP_FCGI_MAX_REQUESTS=12000 export PHPRC export PHP_FCGI_CHILDREN export PHP_FCGI_MAX_REQUESTS exec /usr/bin/php-cgi 

Answer 1

I think clearing cache is an alternative for this issue . Either restart your apache service or add something like apc.php file and set a cron to clear it after specific interval in accordance to your needs.

OR Alternatively

If you have open_dir restrictions in effect or If this is on user account you have to set APC's tmp directory relative to users home directory with proper permissions.

Answer 2

Just for the benefit of the community - this is something unique which was causing havoc for me and I didn't find any instance of this situation asked or answered before in my extensive seach on this issue.

The Issue for getting frequent Internal server errors was that - I had PHP 5.4.27 and Zend Opcache was installed on my server before I migrated my new ecommerce site which used APC cache. This was causing a conflict somewhere and trhowing internal server error.

After removind Zend Opcache, Another factor was apc.include_once_override was set to '1'. It caused page distortions, I had read about this somewhere so was able to immediately pin point and et to '0'.

Now it works fine like charm !!! and I am so relieved after a month's battle.