BIND keeps on crashing

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#1 Sun, 11/25/2012 - 23:03
Swifty

BIND keeps on crashing

I am facing a strange error. Every now and then BIND DNS Server crashes randomly. Sometimes it works for 2-3 days, sometimes for only 5 mins. Virtualmin didn't give me this problem before.

Also, is there any way to increase the virtual memory in virtualmin? I seem to have only 63MB virtual memory in my 512 MB vps and it is always used up 90-100% . It's giving MySQL errors. Funnily enough, Real memory usage is just 20-40%

Mon, 11/26/2012 - 00:03
andreychek

Howdy,

Are you by chance using an OpenVZ-based VPS? If so, could you paste your /proc/user_beancounters file? Thanks!

-Eric

Mon, 11/26/2012 - 02:13
Swifty

No. I am using a Xen based VPS.

Tue, 11/27/2012 - 00:00
andreychek

We see a lot of unusual crashes on OpenVZ due to the way the limits are setup, I had wondered if maybe that's what you were seeing.

It is possible what you're seeing is a RAM problem though, as you had mentioned.

What output do you see if you run the command "free -m"?

Also, there's some documentation here on limiting the amount of RAM being used:

https://www.virtualmin.com/documentation/system/low-memory

Tue, 11/27/2012 - 10:28
Swifty

I am including a screenshot of RAM and virtual memory usage.

And here is the free -m total used free shared buffers cached Mem: 497 411 86 0 83 194 -/+ buffers/cache: 133 364 Swap: 63 63 0

Tue, 11/27/2012 - 13:58
Locutus

You can't increase the virtual memory in Virtualmin (even though I have to admit that the name implies you should be able to ;) ). Virtual memory size is simply the size of the swap partition or file. To get more swap space, you have to enlarge that partition/file (or add another one). You can query the existing swap spaces using swapon -s.

Anything in the logs when BIND crashes? Usually, such things don't happen just like that without any trace.

Tue, 11/27/2012 - 20:16
Swifty

Main concern is why virtual memory is used 99% when dedicated memory is available almost 50+%.

BIND crashed again. data/named.run logs are empty.

/var/log/messages shows OOM errors. And thats for swap memory. System memory seems to have been used only 50%.

Tue, 11/27/2012 - 22:33
andreychek

Howdy,

It looks like you only have 64MB of swap memory... with your main memory already running at about 200MB usage, it wouldn't be too hard to run out of RAM if a few new processes launched at the same time (such as a bot hitting your website, or some cron jobs running).

Did you by chance go through the low-memory guide? That contains a lot of ideas for how to keep RAM from causing problems.

In addition to that, you probably also want to add an additional swap file as Locutus mentioned. I might suggest 512MB of swap space. But I'd only do that after following the suggestions in the guide, those can make a really big difference as to memory usage.

-Eric

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