bind 8.2.4: limiting used memory?

Brad Knowles brad.knowles at skynet.be
Tue Aug 7 11:05:08 UTC 2001


At 9:02 AM +0200 8/7/01, Michael Renzmann wrote:

>  The dns cache is meant to help a bit with saving some of the dns
>  queries. Most of the networks it is used in won't query that much, and
>  networks that do it will most likely already have a "huge" dns cache
>  seperated from the router. So it must not be the perfect caching
>  solution with "as many ram as it needs".

	The thing is that saving a little time with certain DNS queries 
is likely to mean absolutely nothing in the grand scheme of things 
with a device like this.  Assuming that it is used as some sort of 
SOHO firewall/router device, you're going to be pretty much 
completely dominated by network latency, and saving a few 
milliseconds by caching only the ten most common queries is just not 
going to buy you a whole lot.


	I've been thinking myself about taking something like the 
CerfBoard or maybe the CerfCube (see <http://www.intrinsyc.com/>) and 
running a "pico" version of NetBSD on the device (which has only 32MB 
of flash RAM on-board, along with some serial ports, a 10Base-T 
Ethernet port, and a header for a CompactFlash card), and then 
hooking up one of the upcoming CompactFlash format 802.11b 
WiFi-certified WLAN cards, and basically cooking up my own 
firewall/router/bridge.

	But I wouldn't dream of running any kind of nameserver on this 
tiny little thing.  IMO, it just doesn't have the horsepower, much 
less the memory.  Even if you plugged an IBM 1GB CompactFlash II card 
in the expansion header, I don't think that the thing could use that 
as RAM in which to execute, although it could probably boot from it.

>  I did all these things last time, and iirc the executable was somewhere
>  near the 1 MB size. But nevertheless I will try again, the last try
>  happened quite a while ago.

	I would sincerely wonder whether it would be possible to get the 
executable down below 1MB.  Once you're down into the range of a 
"pico" application like this, you've got to use all sorts of 
non-standard ways to trim libraries and system calls that aren't 
used, and just linking the thing with shared libraries and stripping 
the binary ain't gonna do that.

-- 
Brad Knowles, <brad.knowles at skynet.be>

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