Nginx – Debian x86_64 + Nginx + PHP5-FPM optimization

debian-lennynginxphp-fpmx86-64

I used to have a VPS (512MB) from Linode and I was running nginx + php5-fpm (which comes with php5.3.3) on Debian Lenny (i686). The total memory usage was about 90-100MB.

Now I have another VPS (different hosting company) and I also run nginx + php5-fpm on Debian Lenny (x86_64). The system is 64-bit, so the memory usage is higher now, about 210-230MB, which I think is too much.

Here is my php5-fpm.conf:

pm = dynamic
pm.max_children = 5
pm.start_servers = 2
pm.min_spare_servers = 2
pm.max_spare_servers = 5
pm.max_requests = 300

That's what top command tells me:

top - 15:36:58 up 3 days, 16:05,  1 user,  load average: 0.00, 0.00, 0.00
Tasks: 209 total,   1 running, 208 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0%us,  0.0%sy,  0.0%ni, 99.9%id,  0.1%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:    532288k total,   469628k used,    62660k free,    28760k buffers
Swap:  1048568k total,      408k used,  1048160k free,   210060k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
22806 www-data  20   0  178m  67m  31m S    1 13.1   0:05.02 php5-fpm
 8980 mysql     20   0  241m  55m 7384 S    0 10.6   2:42.42 mysqld
22807 www-data  20   0  162m  43m  22m S    0  8.3   0:04.84 php5-fpm
22808 www-data  20   0  160m  41m  23m S    0  8.0   0:04.68 php5-fpm
25102 www-data  20   0  151m  30m  21m S    0  5.9   0:00.80 php5-fpm
10849 root      20   0 44100 8352 1808 S    0  1.6   0:03.16 munin-node
22805 root      20   0  145m 4712 1472 S    0  0.9   0:00.16 php5-fpm
21859 root      20   0 66168 3248 2540 S    1  0.6   0:00.02 sshd
21863 root      20   0 66028 3188 2548 S    0  0.6   0:00.06 sshd
 3956 www-data  20   0 31756 3052  928 S    0  0.6   0:06.42 nginx
 3954 www-data  20   0 31712 3036  928 S    0  0.6   0:06.74 nginx
 3951 www-data  20   0 31712 3008  928 S    0  0.6   0:06.42 nginx
 3957 www-data  20   0 31688 2992  928 S    0  0.6   0:06.56 nginx
 3950 www-data  20   0 31676 2980  928 S    0  0.6   0:06.72 nginx
 3955 www-data  20   0 31552 2896  928 S    0  0.5   0:06.56 nginx
 3953 www-data  20   0 31552 2888  928 S    0  0.5   0:06.42 nginx
 3952 www-data  20   0 31544 2880  928 S    0  0.5   0:06.60 nginx

So, the question is there any way to use less memory? Btw, I have 16 cores and it would be nice to make use of them…

Best Answer

  • PHP, NGINX

With the little RAM you have your VPS will be swapping long before you'll use all the cores - just forget about it: run 1 nginx worker process - with will be able to handle WAY more requests than you need.

Since you are most likely running PHP from Lenny distro you have an awful lot of stuff compiled into it. Recompiling PHP will save you some RAM. So will not loading the extensions you don't need - check in php.ini what is being loaded.

PHP-FPM sends requests from queue to workers (round robin), so you can reduce number child processes to 3-4 if you have to - if there are more requests they will just wait for their turn.

  • Rest of the vps

Check what services you are running and if you really need them. Default installation includes a lot of things

If you have saslauthd running and you want it to be running be sure to add a cron job that will restart it on daily basis - it has had a nasty memory leak for ages now and I've seen it bloat to 1.5GB in about two weeks on one of my boxes.

Related Topic