DNS server running low on free mem

[Simon Waters]

Elias wrote:
> 
> I noticed that over a period of a month or two, my DNS servers will run extremely low on memory. My machines are equipped with 1024 MB of mem, but after a while it drops down to less than 10MB free. Restarting the named daemon does not help at all cos the free mem will shoot up to around 200MB when I first restart it, then after a few days it'll go back to < 10MB. The only solution so far is to restart the machines. Is this normal for a DNS server? I'm still new at this and have basically no experience at all in DNS behaviour. BTW, I've just upgraded to use BIND 8.3.4. I've tried running BIND 8.3.2, 8.3.3 and also 8.2.3, but all give the same results. Thanks!

BIND isn't hugely smart on memory usage, but it can be regulated
if necessary.

First question, if the machines have 1GB of RAM, why is only
200MB free after starting BIND? Are you loading a huge number of
zonesor records? Are the machines doing something else? Are they
recursive name servers? Why aren't you running BIND 9 as
recommended?

What OS, and are you sure you are accounting the memory
correctly, many OSes will utilise spare memory as disk cache,
and so report low free memory, which stays at the same low
figure as memory is used.