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High RAM usage, but why?
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High RAM usage, but why?

edited December 2011 in General

Hey everyone.

I have two lowend VPSes I use for development/testing. A 128MB Xen VPS running Debian, Apache, MySQL and PHP and another VPS with 384MB of RAM running Deiban, Nginx, MySQL and PHP.

Both VMs have 'stock configurations', in that the software stacks have been unmodified from downloading/installation.

My question is, is it normal for a VM with no use and such a basic setup to require 100+MB of RAM?

The LAMP stack on the 128MB Xen platform uses 126MB on a straight-up default configuration.

The LEMP stack on the 384MB OpenVZ platform uses 183MB on a straight-up default configuration.

But why?

root@vps:~# ps aux
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.1   2024   676 ?        Ss   Nov30   0:01 init [2]      
root      1383  0.0  0.2   8664   792 ?        Ss   Nov30   0:00 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 2
root      1384  0.0  0.1   8664   508 ?        S    Nov30   0:00 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 2
root      1398  0.0  0.1   1732   652 ?        Ss   Nov30   0:00 /sbin/syslogd
root      1434  0.0  0.2   2284   844 ?        Ss   Nov30   0:00 /usr/sbin/cron
root      1583  0.0  0.2   2388   836 ?        Ss   Nov30   0:00 /usr/sbin/xinetd -pidfile /var/run/xinetd.pid -stayalive -inetd_compat -inetd_ipv6
root      1605  0.0  0.3   9988  1548 ?        Ss   Nov30   0:00 sendmail: MTA: accepting connections          
bind      5233  0.0  2.3  42724  9216 ?        Ssl  Nov30   0:00 /usr/sbin/named -u bind
root      5331  0.0  0.2   5484   968 ?        Ss   Nov30   0:00 /usr/sbin/sshd
root      5377  0.0  0.7   5340  2860 ?        Ss   Nov30   0:00 /usr/sbin/apache2 -k start
www-data  5427  0.0  0.7   5668  2820 ?        S    Nov30   0:00 /usr/sbin/apache2 -k start
www-data 17654  0.0  0.6   5500  2648 ?        S    Nov30   0:00 /usr/sbin/apache2 -k start
root     18428  0.0  0.3   2680  1236 ?        S    Nov30   0:00 /bin/sh /usr/bin/mysqld_safe
mysql    19564  0.0  4.7 137212 18636 ?        Sl   Nov30   0:02 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/va
root     19566  0.0  0.1   1664   584 ?        S    Nov30   0:00 logger -t mysqld -p daemon.error
www-data 19721  0.0  0.6   5612  2692 ?        S    Nov30   0:00 /usr/sbin/apache2 -k start
www-data 19722  0.0  0.6   5500  2648 ?        S    Nov30   0:00 /usr/sbin/apache2 -k start
www-data 21540  0.0  0.6   5492  2596 ?        S    Nov30   0:00 /usr/sbin/apache2 -k start
root     22320  0.0  0.7   8540  3012 ?        Ss   04:47   0:00 sshd: root@pts/0 
root     22342  0.0  0.4   2968  1652 pts/0    Ss   04:48   0:00 -bash
root     22369  0.0  0.7   8540  3012 ?        Ss   04:50   0:00 sshd: root@notty 
root     22371  0.0  0.2   1920   796 ?        Ss   04:50   0:00 /usr/lib/openssh/sftp-server
root     22409  0.0  0.2   2344   928 pts/0    R+   05:01   0:00 ps aux

Comments

  • Hell, even when I used the lowendscript or the Centmin scripts to install the software stacks I -STILL- get high ram usage when in fact I should be using 40-60MB max. Why is that?

  • Apache, Mysql, sendmail and Openssh use tons of RAM so i guess it is normal.

  • Well, I guess my next question would be what (in particular) should I do to tweak Apache and MySQL to perform their (easy/simple) task of serving practically nothing? They're both dev VPSes each with stock Wordpress installation on them with no traffic. I thought the amount of RAM for both would be enough to serve just a stock wordpress install. I set these up so I could get more familiar with Apache and Nginx and learn how to stop relying on things such as cPanel (Even though I got a nice cPanel VPS elsewhere for production sites, hehe) and to become more familiar with OSes other than CentOS.

    Thanks.

  • I always reboot after running LEScript just to see what happens with memory. Running apt-get seems to use up available memory.

    Are you sure you're not looking at memory being put aside for cache?

  • Hmm, how would I know/check to see what memory is being used for cache? I think I solved the issued on the LNMP stack, but the LAMP stack on the Xen VM w/128MB ram is still using 126MB when I use 'free -m'.

    I just did a clean reinstall of Debian 5 32bit and installed the lowendscript software stack and it appears to be running as expected now, using just 50MB of RAM with a stock wordpress installation.

    Going to hit it with Loadimpact now to see what the memory does with some 'visits'. ;)

  • I can't read that hell of output u_u

    And where says 126MB or 183MB?

  • MySQL INNODB uses about 100MB on some systems. Just disabling it alone frees up a good deal of memory. Then again, MySQL MyISAM is useless as a reliable database engine so you're better off moving to PostgreSQL or SQLite.

  • Go59954Go59954 Member
    edited December 2011

    @Xeoncross said: MySQL INNODB uses about 100MB on some systems. Just disabling it alone frees up a good deal of memory.

    Yeah same thought to try that, also with the difference in OVZ and XEN memory allocation, anyway, @op in Debian/Ubuntu add "skip-innodb" to /etc/mysql/my.cnf, then restart mysql server and check memory usage.

  • netomxnetomx Moderator, Veteran

    Disable named and you'll see ;)

    named eats a lot of memory

  • @netomx said: Disable named and you'll see

    Yeah. Looks at the VSZ column of named. That's going to use a lot of memory on OpenVZ VPS.

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