I am currently on a mediatemple DV server (basic) 512mb dedicated ram, this is a CentOS based VPS with Plesk and Virtuozzo. My experience with it from day 1 has been bad and I only could sooth my server issues with several caching "Band-aids," but my sites are not as small as they were a year ago either so the issues have worsen.
I have 3 Drupal installs running on separate (plesk) domains, 1 of those drupal installs is a multisite, that consists of 5-6 sites 2 of those sites are bringing in actual traffic. Those caching "Band-aids" I mentioned are APC, which seemed to help alot initially, and Drupal's Boost, which is considered a poorman's Varnish, it makes all my pages static for anonymous users. Last 30day combined estimate on Google Ananlytics: 90k visitors 260k pageviews.
Issue: alot of downtime, I am continually checking if my sites are up, and lately I have been finding it down more than 3 times daily. Restarting Apache will bring it back up, for some time. I have google search every error message and looked up ways to optimize my DV server, and I am beyond stump what is my next move. Is this server bad, have I hit a impossibly low restriction such as the 12mb kernel memory barrier (kmemsize), is it on my end, do I need to optimize some more?
*I have provided as much information as I can below, any help or suggestions given will be appreciated
Common Error messages I see in the log:
[error] (12)Cannot allocate memory: fork: Unable to fork new process
[error] make_obcallback: could not import mod_python.apache.\n
Traceback (most recent call last):
File "/usr/lib/python2.4/site-packages/mod_python/apache.py", line 21, in ?
import traceback
File "/usr/lib/python2.4/traceback.py", line 3, in ?
import linecache
ImportError: No module named linecache
[error] python_handler: no interpreter callback found.
[warn-phpd] mmap cache can't open /var/www/vhosts/***/httpdocs/*** - Too many open files in system (pid ***)
[alert] Child 8125 returned a Fatal error... Apache is exiting!
[emerg] (43)Identifier removed: couldn't grab the accept mutex
[emerg] (22)Invalid argument: couldn't release the accept mutex
cat /proc/user_beancounters:
Version: 2.5
uid resource held maxheld barrier limit failcnt
41548: kmemsize 4582652 5306699 12288832 13517715 21105036
lockedpages 0 0 600 600 0
privvmpages 38151 42676 229036 249036 0
shmpages 16274 16274 17237 17237 2
dummy 0 0 0 0 0
numproc 43 46 300 300 0
physpages 27260 29528 0 2147483647 0
vmguarpages 0 0 131072 2147483647 0
oomguarpages 27270 29538 131072 2147483647 0
numtcpsock 21 29 300 300 0
numflock 8 8 480 528 0
numpty 1 1 30 30 0
numsiginfo 0 1 1024 1024 0
tcpsndbuf 648440 675272 2867477 4096277 1711499
tcprcvbuf 301620 359716 2867477 4096277 0
othersockbuf 4472 4472 1433738 2662538 0
dgramrcvbuf 0 0 1433738 1433738 0
numothersock 12 12 300 300 0
dcachesize 0 0 2684271 2764800 0
numfile 3447 3496 6300 6300 3872
dummy 0 0 0 0 0
dummy 0 0 0 0 0
dummy 0 0 0 0 0
numiptent 14 14 200 200 0
TOP: (In January the load avg was really high 3-10, I was able to bring it down where it is currently is by giving APC more memory play around with)
top - 16:46:07 up 2:13, 1 user, load average: 0.34, 0.20, 0.20
Tasks: 40 total, 2 running, 37 sleeping, 0 stopped, 1 zombie
Cpu(s): 0.3% us, 0.1% sy, 0.0% ni, 99.7% id, 0.0% wa, 0.0% hi, 0.0% si
Mem: 916144k total, 156668k used, 759476k free, 0k buffers
Swap: 0k total, 0k used, 0k free, 0k cached
MySQLTuner: (after optimizing every table and repairing any table with overage I got the fragmented count down to 86)
[--] Data in MyISAM tables: 285M (Tables: 1105)
[!!] Total fragmented tables: 86
[--] Up for: 2h 44m 38s (409K q [41.421 qps], 6K conn, TX: 1B, RX: 174M)
[--] Reads / Writes: 79% / 21%
[--] Total buffers: 58.0M global + 2.7M per thread (100 max threads)
[!!] Query cache prunes per day: 675307
[!!] Temporary tables created on disk: 35% (7K on disk / 20K total)
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You're out of memory (RAM).
Upgrading to 1 or 2 GB should give a massive performance boost.
It looks like that doubles or triples your costs, so you may want to look at other VPS providers.
From LapTop006 -
If you're only using the VPS for Drupal sites then you might be better off running Aegir rather than a full-blown control panel like Plesk. No idea if or how much that would save in resources, but it might be worth considering.
There are quite a few articles on the best way of optimising Drupal, but they usually involve throwing quite a bit of ram at it. This collection is a good start. But first, make sure you aren't running any modules you don't need to.
You may also want to consider whether to move MySQL to a separate server (though probably not for Drupal since it tends to use the database quite heavily). And if most of your traffic is for anonymous users then it might be worth considering getting an extra server to run a caching forward proxy and/or memcached.
But extra memory on this server is probably the easiest and best solution. 512Mb isn't a lot for a combined web/MySQL server running some fairly big Drupal sites.
From kaerast
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