Wow! The memory eater was security2 ...
With the module enabled (120-160MB per process) ...
With the module disabled (9-15MB per process) ...
Module security2 disabled.
Thank's for your answer Dino. That's enough for me.
I didn’t really think a module would cause this change in memory usage, which is why I haven’t dedicated myself to disabling them one by one. But I was clearly wrong. Thank you again.
For your information, my problem was understand why so much difference between to systems because I want to optimize some parameters like: ServerLimit, StartServers, MinSpareServers, MaxSpareServers, MaxClients and MaxRequestsPerChild
I need to know the memory used per each Apache process to find the MaxClients value.
Missatge de Dino Ciuffetti <
dino@xxxxxxxxx> del dia dl., 17 de maig 2021 a les 14:54:
>
> Try to comment out mod_security, it's a module that use enough memory.
> Also on server2 there are modules not loaded on server1. BTW what's your problem? Your server is plenty of ram and RSS memory is not creating any problem. Right?
>
>
> 17 maggio 2021 13:34, "Marc Serra" <
mserra@xxxxxxxxx> wrote:
>
> Hi to all,
> I already posted this question to
stackoverflow.com but no answer after 9 days:
https://stackoverflow.com/questions/67439771/why-so-much-difference-in-memory-used-per-process-in-apache2-between-two-differe> I hope the apache gurus in this list can help me :)
> I have a pair of Ubuntu dedicated servers...
>
> Server1:
> Ubuntu 16.04.7 (64 bits)
> 16GB RAM
> 8 Xeon CPU
> Apache 2.4.18
> MPM mode: prefork
>
> Server2:
> Ubuntu server 20.04.2 (64 bits)
> 32GB RAM
> 8 Xeon CPU
> 2.4.41
> MPM mode: event
>
> On Server1, each apache2 process uses between 7MB and 18MB of RAM ...
> # ps axo 'user rss cmd' | grep apache | grep -v "\(root\|grep\|tomcat\)"
> www-data 18232 /usr/sbin/apache2 -k start
> www-data 11700 /usr/sbin/apache2 -k start
> www-data 11276 /usr/sbin/apache2 -k start
> www-data 10792 /usr/sbin/apache2 -k start
> www-data 11216 /usr/sbin/apache2 -k start
> www-data 11600 /usr/sbin/apache2 -k start
> www-data 10336 /usr/sbin/apache2 -k start
> www-data 11356 /usr/sbin/apache2 -k start
> www-data 11348 /usr/sbin/apache2 -k start
> www-data 10980 /usr/sbin/apache2 -k start
> www-data 11316 /usr/sbin/apache2 -k start
> www-data 6808 /usr/sbin/apache2 -k start
>
> On Server2, each apache2 process uses between 120MB and 130MB of RAM ...
> # ps axo 'user rss cmd' | grep apache | grep -v "\(root\|grep\|tomcat\)"
> www-data 120436 /usr/sbin/apache2 -k start
> www-data 119784 /usr/sbin/apache2 -k start
> www-data 128720 /usr/sbin/apache2 -k start
> www-data 130208 /usr/sbin/apache2 -k start
>
> Why so much difference in memory used?
>
> After read a few documentation and googleing, I thought about loaded modules, but there are not a lot of difference between each server...
>
> Server1
> # apache2 -M
> Loaded Modules:
> core_module (static)
> so_module (static)
> watchdog_module (static)
> http_module (static)
> log_config_module (static)
> logio_module (static)
> version_module (static)
> unixd_module (static)
> access_compat_module (shared)
> actions_module (shared)
> alias_module (shared)
> auth_basic_module (shared)
> auth_digest_module (shared)
> auth_openidc_module (shared)
> authn_core_module (shared)
> authn_file_module (shared)
> authz_core_module (shared)
> authz_host_module (shared)
> authz_user_module (shared)
> autoindex_module (shared)
> bw_module (shared)
> cgi_module (shared)
> dav_module (shared)
> dav_fs_module (shared)
> dav_lock_module (shared)
> deflate_module (shared)
> dir_module (shared)
> env_module (shared)
> expires_module (shared)
> fcgid_module (shared)
> filter_module (shared)
> headers_module (shared)
> include_module (shared)
> mime_module (shared)
> mpm_prefork_module (shared)
> negotiation_module (shared)
> proxy_module (shared)
> proxy_balancer_module (shared)
> proxy_fcgi_module (shared)
> proxy_http_module (shared)
> rewrite_module (shared)
> setenvif_module (shared)
> slotmem_shm_module (shared)
> socache_shmcb_module (shared)
> ssl_module (shared)
> status_module (shared)
> suexec_module (shared)
> userdir_module (shared)
> Server2
> # apache2 -M
> Loaded Modules:
> core_module (static)
> so_module (static)
> watchdog_module (static)
> http_module (static)
> log_config_module (static)
> logio_module (static)
> version_module (static)
> unixd_module (static)
> access_compat_module (shared)
> aclr_module (shared)
> actions_module (shared)
> alias_module (shared)
> auth_basic_module (shared)
> auth_digest_module (shared)
> auth_openidc_module (shared)
> authn_core_module (shared)
> authn_file_module (shared)
> authz_core_module (shared)
> authz_host_module (shared)
> authz_user_module (shared)
> autoindex_module (shared)
> cgid_module (shared)
> dav_module (shared)
> dav_fs_module (shared)
> dav_lock_module (shared)
> deflate_module (shared)
> dir_module (shared)
> env_module (shared)
> fcgid_module (shared)
> filter_module (shared)
> headers_module (shared)
> include_module (shared)
> mime_module (shared)
> mpm_event_module (shared)
> negotiation_module (shared)
> proxy_module (shared)
> proxy_balancer_module (shared)
> proxy_fcgi_module (shared)
> proxy_http_module (shared)
> remoteip_module (shared)
> reqtimeout_module (shared)
> rewrite_module (shared)
> security2_module (shared)
> setenvif_module (shared)
> slotmem_shm_module (shared)
> socache_shmcb_module (shared)
> ssl_module (shared)
> status_module (shared)
> suexec_module (shared)
> unique_id_module (shared)
> userdir_module (shared)
>
> I already changed MPM mode from Event to Prefork on Server2, with the same results.
>
> What else can I check to understand this difference?
> Thank's!
>
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