A quick update here, I'm starting to believe there is a memory leak in
either the way I've configured or compiled httpd on AWS EC2. I'm running a
t2.small with 4GB memory with LAMP installed and 4 very small (< 5 hits a
day) sites running on it. In my opinion, even with mod_php, Apache should
require no more than 100MB IN TOTAL. That's not, however, the case:
[ec2-user@ip-172-31-21-23 ~]$ free -m
total used free shared buffers cached
Mem: 3954 *3809* 145 19 214 643
-/+ buffers/cache: 2952 1002
Swap: 0 0 0
[ec2-user@ip-172-31-21-23 ~]$ ps aux | grep 'httpd' | awk '{print $6/1024;}'
2.07812
45.9297
9.48438
2648.25
[ec2-user@ip-172-31-21-23 ~]$ ps aux | grep 'httpd' | awk '{print
$6/1024;}' | awk '{avg += ($1 - avg) / NR;} END {print "Num Processes: " NR
" Average: " avg " MB";}'
Num Processes: 4 Average: 676.416 MB
There you have it. A *4GB, $50/mo EC2 server* with the default installation
of LAMP
<http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/install-LAMP.html>, at *96%
utilized memory* and *71%* of the used memory going to 4 Apache processes
(average of 676.4MB per process). If you're wondering how it is installed:
[ec2-user@ip-172-31-21-23 ~]$ httpd -V
Server version: Apache/2.4.27 (Amazon)
Server built: Aug 2 2017 18:02:45
Server's Module Magic Number: 20120211:68
Server loaded: APR 1.5.1, APR-UTIL 1.4.1
Compiled using: APR 1.5.1, APR-UTIL 1.4.1
Architecture: 64-bit
Server MPM: worker
threaded: yes (fixed thread count)
forked: yes (variable process count)
Server compiled with....
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
-D APR_USE_SYSVSEM_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D DYNAMIC_MODULE_LIMIT=256
-D HTTPD_ROOT="/etc/httpd"
-D SUEXEC_BIN="/usr/sbin/suexec"
-D DEFAULT_PIDLOG="/var/run/httpd/httpd.pid"
-D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="conf/mime.types"
-D SERVER_CONFIG_FILE="conf/httpd.conf"
and the loaded modules:
[ec2-user@ip-172-31-21-23 ~]$ httpd -M
Loaded Modules:
core_module (static)
so_module (static)
http_module (static)
access_compat_module (shared)
actions_module (shared)
alias_module (shared)
auth_basic_module (shared)
auth_digest_module (shared)
authz_core_module (shared)
authz_dbd_module (shared)
authz_dbm_module (shared)
authz_groupfile_module (shared)
authz_host_module (shared)
authz_owner_module (shared)
authz_user_module (shared)
autoindex_module (shared)
data_module (shared)
deflate_module (shared)
dir_module (shared)
env_module (shared)
expires_module (shared)
ext_filter_module (shared)
filter_module (shared)
headers_module (shared)
include_module (shared)
info_module (shared)
log_config_module (shared)
mime_module (shared)
negotiation_module (shared)
reqtimeout_module (shared)
request_module (shared)
rewrite_module (shared)
setenvif_module (shared)
slotmem_plain_module (shared)
slotmem_shm_module (shared)
socache_dbm_module (shared)
socache_memcache_module (shared)
socache_shmcb_module (shared)
status_module (shared)
unixd_module (shared)
userdir_module (shared)
version_module (shared)
vhost_alias_module (shared)
watchdog_module (shared)
dav_module (shared)
dav_fs_module (shared)
dav_lock_module (shared)
mpm_worker_module (shared)
ssl_module (shared)
cgid_module (shared)
php5_module (shared)
pagespeed_module (shared)
Thoughts on optimization/memory repair?
Thank you!
On Wed, Sep 6, 2017 at 2:25 PM, Tony DiLoreto <[email protected]
> wrote:
> Thanks Luca, I'll give that a shot. What surprises me is how much each
> process was consuming; at times 250mb each. Are you saying the majority of
> that is for php?
>
> At the end of the day, I'm looking for the optimal configuation for a
> standard Wordpress site server. Given the ubiquity of the platform you'd
> expect more people to have blogged about the required mods and MPM
> settings for this, but I've come back with little.
>
> Do we have a "barebones Wordpress" list of mods that are required?
>
> On Wed, Sep 6, 2017 at 1:30 AM Luca Toscano <[email protected]>
> wrote:
>
>> Hi Tony,
>>
>> usually httpd consumes a very little amount of memory, if it is behaving
>> in that way it is probably due to some module like mod_php. Can you give us
>> a bit more info about your mpm used and the list of modules loaded? For
>> example, the most common use case that we see is mpm-prefork and mod_php
>> causing a ton of RAM consumed (each httpd process allocates memory for a
>> PHP interpreter), meanwhile a solution like mpm-worker|event +
>> mod_proxy_fcgi + php-fpm works way better.
>>
>> My suggestion would be to narrow down what module is really causing your
>> memory to saturate before tuning the mpm.
>>
>> Luca
>>
>>
>> 2017-09-06 1:33 GMT+02:00 Tony DiLoreto <[email protected]>:
>>
>>> Hi Luca,
>>>
>>> Basically my server runs out of free memory and freezes. On AWS I have
>>> to stop/start it again to be able to SSH in. What I'd really like is a
>>> MAX_PERCENTAGE_AVAILABLE_MEMORY directive that limits Apache to <= some
>>> % of free memory. That way it can never halt my system.
>>>
>>> Hope this helps.
>>>
>>> On Tue, Sep 5, 2017 at 1:16 PM Luca Toscano <[email protected]>
>>> wrote:
>>>
>>>> Hi Tony,
>>>>
>>>> 2017-08-31 23:43 GMT+02:00 Tony DiLoreto <[email protected]
>>>> >:
>>>>
>>>>> Hi All,
>>>>>
>>>>> I've been scouring the internet for best practices or heuristics for
>>>>> specifying parameter values of the MPM directives. My server seems to lock
>>>>> up regardless of the values I enter. Are there "rules of thumb" for each
>>>>> MPM type (prefork, worker, event)?
>>>>>
>>>>>
>>>> Can you tell us what do you mean with "lock up"?
>>>>
>>>> Luca
>>>>
>>> --
>>> Tony DiLoreto
>>> President & CEO
>>> Migliore Technologies Inc
>>>
>>> 716.997.2396
>>> [email protected]
>>>
>>>
>>>
>>> miglioretechnologies.com
>>> *The best in the business...period!*
>>>
>>
>> --
> Tony DiLoreto
> President & CEO
> Migliore Technologies Inc
>
> 716.997.2396
> [email protected]
>
>
>
> miglioretechnologies.com
> *The best in the business...period!*
>
--
Tony DiLoreto
President & CEO
Migliore Technologies Inc
716.997.2396
[email protected]
miglioretechnologies.com
*The best in the business...period!*
