Bind and restarts - cacheing DNS data

Barry Margolin barmar at bbnplanet.com
Mon Sep 13 14:58:08 UTC 1999


In article <X1nC3.15321$ei1.30954 at newsfeeds.bigpond.com>,
Reuben Farrelly <reubie at bigpond.com> wrote:
>Occasionally after upgrading a kernel or installing a fairly major upgrade
>of a package on my system, I have to reboot in order for changes to take
>effect (a new kernel being an obvious opportunity).  I understand that in
>doing so, obviously BIND has to be shut down and therefore loses all the
>cached data that it has learnt about various zones that it has recently
>cached.
>
>Is there any way that BIND can write this information out to disk and then
>reread it upon restart?  Obviously cached zone data can't be cached for any
>length of time (most seems to expire or at least need refreshing fairly
>quickly), but it seems pointless to have to lose the entire cache just
>because I need to reboot my machine.  If the machine is only down for a few
>minutes, wouldn't almost all of this data be valid and usable if it weren't
>dumped and could be reread into memory?

No, there's currently no way to maintain the cache across named restarts.
Losing the cache occasionally is not generally considered a serious
problem; the server will quickly load up the common entries after it
restarts.  If the server is down for several minutes due to the reboot, is
it really that much of a problem that it's a tiny bit slower to answer the
first few DNS queries when it starts up?

As long as you don't restart an important nameserver very often, I wouldn't
worry about this much.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.


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