[Users] Memory overflow in an OpenVZ VPS

[Samuli Seppänen]

Forgot to mention that I have monit watching the memory usage of the VPS 
and it goes up steadily, for example:

1:30 PM: mem usage = 75%
2:30 PM: mem usage = 78%
3:25 PM: mem usage = 80%
16:10 PM: mem usage = 100%

At which point memory allocations probably fail and privvmpages 
failcount goes up.


> Hello everybody!
> 
> I'm having problems with OpenVZ memory management. I have (probably) 
> read all the Wiki articles there are that touch that subject, and 
> browsed through the mailing list archives to no avail.
> 
> Most of my OpenVZ VPS'es work just fine after a bit of fiddling, but one 
> of them is misbehaving constantly. It always runs out of memory, no 
> matter how much I give it. It is running 10 instances of a same server 
> to give better interactive responsiveness. I was just wondering if the 
> server program is leaking memory and causing this erratic behavior, or 
> if there is something wrong with my OpenVZ VPS's configuration.
> 
> The physical server runs only this one VPS. The hardware node has 2GB of 
> RAM plus 2GB of swap. The VPS is given roughly 3.5GB of that if 
> available (privvmpages limit). It is guaranteed 2.5GB (vmguarpages 
> barrier). This is FAR more than the server software in question needs, 
> but still it occasionally (and predictably) runs out of memory.
> 
> The strange thing about the VPS is that the HELD values in oomguarpages 
> and privvmpages are _much_ lower than the MAXHELD values - almost 
> triple. There should be no usage peaks that should cause this kind of 
> asymmetry, unless an instance of the server software goes amok.
> 
> The VPS's resource information is shown below. The parameters are not 
> optimized, as you can see, but that not my biggest problem right now :). 
> So can you see anything wrong with these settings, or should I take a 
> look at the server software that is running on the VPS?
> 
> [root at VPS_NODE ~]# cat /proc/user_beancounters
> Version: 2.5
> uid  resource           held    maxheld    barrier      limit    failcnt
> 103: kmemsize       19265157   40765738  183079731  201387704          0
>      lockedpages           0          0       8939       8939          0
>      privvmpages      383368     930126     917504     930000        153
>      shmpages          21647      24239      31099      31099          0
>      dummy                 0          0          0          0          0
>      numproc             229        524       8000       8000          0
>      physpages        236810     485688          0 2147483647          0
>      vmguarpages           0          0     655360 2147483647          0
>      oomguarpages     382472     874046     310999 2147483647          0
>      numtcpsock          532        793       8000       8000          0
>      numflock             18        594       1000       1100          0
>      numpty                1          4        512        512          0
>      numsiginfo            0         39       1024       1024          0
>      tcpsndbuf       3524644    4236356   28258577   61026577          0
>      tcprcvbuf       3530300    6528712   28258577   61026577          0
>      othersockbuf     190060    1737340   14129288   46897288          0
>      dgramrcvbuf           0      41836   14129288   14129288          0
>      numothersock        204       1169       8000       8000          0
>      dcachesize            0          0   39977755   41177088          0
>      numfile           11106      22346      71488      71488          0
>      dummy                 0          0          0          0          0
>      dummy                 0          0          0          0          0
>      dummy                 0          0          0          0          0
>      numiptent            10         10        200        200          0
> 
> [root at HOST_NODE ~]# free
>              total       used       free     shared    buffers     cached
> Mem:       2073344    2017716      55628          0      66928     954828
> -/+ buffers/cache:     995960    1077384
> Swap:      2031608     586508    1445100
> 
> 
> Anyways, thanks for a great Open Source virtualization project!
> 
> Samuli Seppänen
> _______________________________________________
> Users mailing list
> Users at openvz.org
> https://openvz.org/mailman/listinfo/users
>