[Pdns-users] PDNS 2.9.21 using LOTS of virtual memory...

[Stephen Manchester]

I was noticing it's mem usage in top.  Resident memory is usually  
less than 10k.  It is also showing the high VM usage in /proc/ 
meminfo.  We've been having some oom issues lately, and this caught  
my eye as being not right.  Not that VM would directly cause oom  
condition, but it does seem like a bug as why would it need so much?   
There might be a correlating bug that actually causes all the memory  
to go resident at some strange time, which would cause an oom condition.

I did set the backend cache to 5 minutes, and the packet cache to 1  
minute.  most of our records never change, we just add to them so  
this seemed a good way to reduce load. All other config options are  
pretty much default.

What would/could it be allocating that much virtual memory for?


On Sep 20, 2007, at 2:54 PM, bert hubert wrote:

> On Thu, Sep 20, 2007 at 02:52:50PM -0700, Stephen Manchester wrote:
>> I've been running PDNS server on CentOS 4.4 for about 3 months now.
>> I've noticed that PDNS allocates a LOT of virtual memory as it's
>> running, and never frees it up.  It can do this at an incredibly fast
>> rate at times, as much as 2.9GB within 24 hours.  Has anyone seen
>> this before and know why it might be happening?
>
> Stephen,
>
> How do you measure its actual usage?
>
> The trick is to look at the 'RES' entry of 'top' for example.
>
> Other measurements can be a tad confusing, I think due to the  
> static linking
> we employ in our RPMs. The Kees Monshouwer RPMs might be better in  
> this
> respect: ftp://ftp.monshouwer.com/pub/linux/pdns-server
>
> 	Bert
> -- 
> http://www.PowerDNS.com      Open source, database driven DNS Software
> http://netherlabs.nl              Open and Closed source services