hardware requirements per hits

Fajar A. Nugraha fajar at fajar.net
Wed Aug 19 09:11:38 UTC 2009

On Wed, Aug 19, 2009 at 12:47 AM, Subhan Malick<malicks at illinois.edu> wrote:
> On 8/17/09 10:15 PM, Fajar A. Nugraha wrote:
>> Here are some pointers from my experience though:
>> - syslog query logging is expensive. NEVER enable it. If you need to
>> log client queries, log it directly to file instead.
> I would like to hear more about why this is so. We are currently debating
> sending query logs to a remote syslog server to enhance some security tools.

It depends on your requirement.
In my case, sending query log to syslog makes disk I/O the bottleneck.
Not really sure why logging to file directly fix this issue, perhaps
syslog does a sync() for every line or something.

> We are running BIND 9.6.1-P1 with multithreading enabled on RHEL 4 (2
> dual-core 2.8 GHz Opterons with 1MB cache, 4G of RAM). I have run some tests
> and while there is some queries/sec hit, the RTTs are not terrible.

>  Queries per second:   2425.385916 qps

I got around 6000 qps on a smiliar test. Jinmei mentioned something
about getting 24k qps on a 4-way Opteron.

Again, it depends on your requirement. If your load is low enough, you
might be able to live with performance penalty imposed by syslog.


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