OpenVZ RAM Questions

exaviorn

Hi!
I'm having a few issues with my provider's burstable Ram, my VPS package is 128mb guaranteed, with 256 burst. However my VPS seems to be claiming I'm using more ram than I think I am actually using:
Here is a ps_mem.py output that claims I am only using 86.5mb ram:
`Private + Shared = RAM used Program

76.0 KiB + 42.5 KiB = 118.5 KiB logger
152.0 KiB + 36.5 KiB = 188.5 KiB syslogd
168.0 KiB + 48.0 KiB = 216.0 KiB init
268.0 KiB + 54.0 KiB = 322.0 KiB xinetd
272.0 KiB + 56.0 KiB = 328.0 KiB cron
376.0 KiB + 65.0 KiB = 441.0 KiB memcached
412.0 KiB + 53.0 KiB = 465.0 KiB exim4
424.0 KiB + 174.5 KiB = 598.5 KiB sudo
292.0 KiB + 321.0 KiB = 613.0 KiB mysqld_safe
488.0 KiB + 214.5 KiB = 702.5 KiB vsftpd
544.0 KiB + 321.0 KiB = 865.0 KiB bash
932.0 KiB + 492.0 KiB = 1.4 MiB nginx (2)
1.3 MiB + 1.1 MiB = 2.4 MiB sshd (3)
4.5 MiB + 629.5 KiB = 5.1 MiB varnishd (2)
6.9 MiB + 99.0 KiB = 7.0 MiB mysqld

48.9 MiB + 16.9 MiB = 65.8 MiB php5-fpm (6)

                     86.5 MiB

=================================`

However free and SolusVM claim that I am in fact using 227mb:
total used free shared buffers cached Mem: 256 227 28 0 0 0 -/+ buffers/cache: 227 28 Swap: 0 0 0

I'm mostly used to Xen VPS', so my idea of what burstable ram is and how it works may be wrong, but this does look like something's wrong, especially when the setup here is absolutely identical to another VPS (Xen) that I own that only uses about 70-80mb ram

Thanks in advance!

dmmcintyre3

@DotVPS that doesn't apply on non vswap openvz.

@exaviorn OpenVZ without vswap support limits memory usage based on allocation instead of the real usage. ps_mem.py shows the real usage, not what is allocated. If you were running that exact setup on a Xen VPS you would use around 85mb-90mb ram.

exaviorn

@DotVPS said: Scrap the above is your VPS on a RHEL 6 node with vswap?

No, it's a Debian 6 node with Hostigation (I'm not sure if it is vswap or not)

dmmcintyre3

@exaviorn said: No, it's a Debian 6 node with Hostigation (I'm not sure if it is vswap or not)

The OS on your VPS isn't the OS on the node. Hostigation only uses vswap openvz on their backup node.

exaviorn

@dmmcintyre3 said: The OS on your VPS isn't the OS on the node

Sorry, I meant container, my VPS itself is Debian 6

dmmcintyre3

Non vswap OpenVZ's memory limits are based on memory allocation (what your stuff thinks it needs) not it's real usage. Most hosts don't use vswap openvz because of stability issues.

On my Hostigation KVM VPS ps_mem.py and free -m report simular usage.

[root@tiger ~]# ps_mem.py;free -m
 Private  +   Shared  =  RAM used       Program 

116.0 KiB +  27.5 KiB = 143.5 KiB       acpid
192.0 KiB +  36.0 KiB = 228.0 KiB       dbus-daemon
324.0 KiB +  41.0 KiB = 365.0 KiB       auditd
324.0 KiB +  65.5 KiB = 389.5 KiB       init
348.0 KiB + 153.0 KiB = 501.0 KiB       mingetty (6)
216.0 KiB + 328.0 KiB = 544.0 KiB       mysqld_safe
596.0 KiB +  51.5 KiB = 647.5 KiB       crond
488.0 KiB + 331.0 KiB = 819.0 KiB       bash
660.0 KiB + 188.0 KiB = 848.0 KiB       syslog-ng (2)
752.0 KiB +  98.0 KiB = 850.0 KiB       exim
376.0 KiB + 494.5 KiB = 870.5 KiB       udevd (3)
612.0 KiB + 331.0 KiB = 943.0 KiB       nsd (3)
  1.5 MiB + 228.5 KiB =   1.7 MiB       qpidd
  1.7 MiB +  41.0 KiB =   1.8 MiB       ircd
  2.0 MiB + 342.0 KiB =   2.4 MiB       scrd
  1.9 MiB + 569.0 KiB =   2.4 MiB       sshd (2)
  1.8 MiB + 868.0 KiB =   2.6 MiB       nginx (2)
  4.1 MiB + 162.5 KiB =   4.3 MiB       services
  4.3 MiB + 317.0 KiB =   4.6 MiB       openvpn
  4.8 MiB +  93.5 KiB =   4.9 MiB       munin-node
  2.0 MiB +   3.2 MiB =   5.2 MiB       php-fpm (2)
  6.3 MiB + 477.5 KiB =   6.7 MiB       znc
 11.7 MiB + 321.0 KiB =  12.0 MiB       mysqld
---------------------------------
                         55.6 MiB
=================================

 Private  +   Shared  =  RAM used       Program 

             total       used       free     shared    buffers     cached
Mem:           115         99         15          0          6         34
-/+ buffers/cache:         58         57
Swap:          236          0        236

exaviorn

@dmmcintyre3 said: Non vswap OpenVZ's memory limits are based on memory allocation (what your stuff thinks it needs)

Is there any way to tell process by process what it's allocation is?

miTgiB

@exaviorn said: No, it's a Debian 6 node with Hostigation

As @dmmcintyre3 stated, only the backup node runs EL6, and vSwap is disabled, all other OpenVZ nodes are EL5

dmmcintyre3

@exaviorn said: Is there any way to tell process by process what it's allocation is?

The only way I know of is to run free -m; stop the process; run free -m again; start the process and then check the difference. mysql, memcache and php are the 3 I would look at first.

efball

Also try "vzfree" to get more info:
http://hostingfu.com/article/vzfree-checking-memory-usage-inside-openvz-ve

yomero

It seems like DotVPS doesn't know anything about this business...