I started using the built-in PHP OPcache of PHP 5.6 and am facing a problem now. I set it up to use up to 1 GB of RAM, which is highly enough for my websites but it never get get it to use the full 1 GB of RAM. The cache is cleared many times before it would allocate this limit as you can see on this munin graph:
So every few days it deletes all files from the cache and starts again to cache them.
First I thought that the problem is the variable
opcache.max_wasted_percentage but it doesn’t care to which value I set it. My configuration is the following:
; configuration for php ZendOpcache module ; priority=05 zend_extension=opcache.so opcache.enable = 1 opcache.enable_cli = 1 opcache.memory_consumption = 1024 opcache.interned_strings_buffer = 128 opcache.blacklist_filename = /etc/php5/opcache_blacklist.txt opcache.max_accelerated_files = 65407 opcache.revalidate_freq = 5 opcache.fast_shutdown = 1 opcache.max_wasted_percentage = 90 opcache.enable_file_override = 1
I’m using it in an environment of the latest Debian Jessie with nginx and FastCGI.
I want to achieve that the cache only gets cleared when the memory consumption has reached the 1 GB. I already tried a very minimal configuration looking like this:
; configuration for php ZendOpcache module ; priority=05 zend_extension=opcache.so opcache.enable = 1 opcache.enable_cli = 1 opcache.memory_consumption = 1024
Even then the problem still persists.
If the FPM config is needed:
user = www group = www listen = 127.0.0.1:9002 listen.owner = www listen.group = www listen.allowed_clients = 127.0.0.1 pm = ondemand pm.max_children = 100 pm.process_idle_timeout = 5s;
[PHP] engine = On short_open_tag = Off asp_tags = Off precision = 14 y2k_compliance = On output_buffering = 4096 zlib.output_compression = Off implicit_flush = Off unserialize_callback_func = serialize_precision = 17 allow_call_time_pass_reference = Off safe_mode = Off safe_mode_gid = Off safe_mode_include_dir = safe_mode_exec_dir = safe_mode_allowed_env_vars = PHP_ safe_mode_protected_env_vars = LD_LIBRARY_PATH disable_functions = escapeshellcmd, exec, ini_restore, passthru, popen, proc_nice, proc_open, shell_exec, show_source, system disable_classes = zend.enable_gc = On expose_php = Off max_execution_time = 120 max_input_time = 300 memory_limit = 512M error_reporting = E_ALL & ~E_DEPRECATED display_errors = Off display_startup_errors = Off log_errors = On log_errors_max_len = 1024 ignore_repeated_errors = Off ignore_repeated_source = Off report_memleaks = On track_errors = Off html_errors = Off error_log = /var/log/nginx/php_error.log variables_order = "GPCS" request_order = "GP" register_globals = Off register_long_arrays = Off register_argc_argv = Off auto_globals_jit = On post_max_size = 2000M magic_quotes_gpc = Off magic_quotes_runtime = Off magic_quotes_sybase = Off auto_prepend_file = auto_append_file = default_mimetype = "text/html" doc_root = user_dir = enable_dl = Off cgi.fix_pathinfo = 0 file_uploads = On upload_max_filesize = 200M max_file_uploads = 200 allow_url_fopen = On allow_url_include = Off default_socket_timeout = 60
Hopefully I can found here anyone who already faced this problem and could solve it. So my final question is: How can I configure the OpCache so that it just gets cleared when the usable memory is full?
OPcache dumps the entire cache and starts over whenever it hits any of its configured limits. This behavior is a bit annoying, but it’s what we’re stuck with for now.
Since you aren’t hitting the memory limit, my guess is that you’re hitting a limit you aren’t collecting metrics on.
In particular, you aren’t collecting metrics on the number of cache keys (files) in use. I suspect you are hitting the limit of 65407 which you have configured, and should raise it.
Whether you are hitting that limit or not, you should begin gathering this data.
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