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vzplit bug? [message #35582]

Mon, 06 April 2009 18:58

daaz
Messages: 3
Registered: April 2009

Junior Member

Hello,

I'm using OpenVZ on CentOS 5.2 (please see below for kernel and tools version). I created a few large containers using vzsplit, but had to manually increase privvmpages on them because of failcnts. I noticed that several settings do not change with the number of containers:

# for i in 1 2 3 4; do vzsplit -n $i |grep VM; echo "---------"; done
The optimal swap space size is 7877 Mb, twice bigger than the RAM size

VMGUARPAGES="605025:9223372036854775807"
PRIVVMPAGES="605025:665527"
---------
The optimal swap space size is 7877 Mb, twice bigger than the RAM size

VMGUARPAGES="605025:9223372036854775807"
PRIVVMPAGES="605025:665527"
---------
The optimal swap space size is 7877 Mb, twice bigger than the RAM size

VMGUARPAGES="605025:9223372036854775807"
PRIVVMPAGES="605025:665527"
---------
The optimal swap space size is 7877 Mb, twice bigger than the RAM size

VMGUARPAGES="605025:9223372036854775807"
PRIVVMPAGES="605025:665527"
---------

privvmpages does not change until "vzsplit -n 27", although
vmguarpages does change after "vzsplit -n 4". Is this a bug?

My kernel/library versions follow.

Thank you,

daaz

# uname -a
Linux myhost.mydomain 2.6.18-92.1.18.el5.028stab060.2 #1 SMP Tue Jan 13 11:38:36 MSK 2009 x86_64 x86_64 x86_64 GNU/Linux

# rpm -qa|grep vz
vzctl-lib-3.0.23-1
vzquota-3.0.12-1
ovzkernel-2.6.18-92.1.18.el5.028stab060.2
vzctl-3.0.23-1

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Re: vzplit bug? [message #35594 is a reply to message #35582]

Tue, 07 April 2009 13:53

maratrus
Messages: 1495
Registered: August 2007
Location: Moscow

Senior Member

Hi,

at first glance it's a sensible behavior since privvmpages accounts allocated (but possibly not used) memory.

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Re: vzplit bug? [message #35640 is a reply to message #35594]

Thu, 09 April 2009 18:15

daaz
Messages: 3
Registered: April 2009

Junior Member

Thank you, maratrus. But, it seems to me that something isn't right if you get the same config for a container supposedly having 1/2 the resources of the hardware node and for one with 1/5 the resources. I ended up by starting with the config generated by "vzsplit -n 6" and multiplying most parameters by 2 and 3, respectively, to get containers with 1/3 and 1/2 the resources of the harware. I did that for all parameters except NUMIPTENT, DISKSPACE, DISKINODES, and CPUUNITS. Hopefully, I'm not doing anything terribly wrong.

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