NSD CPU time consumption in slave config

Jan Boysen - servage.net janboysen at servage.net
Fri Jul 6 18:04:53 UTC 2007

Mark Santcroos wrote:
> Hi Jan,
> Thank you for your sharing your experiences.

> Jan Boysen - servage.net wrote:
>> I have running a nsd test server with about 100.000 zones as master and
>> one as slave in my test environment. The master works pretty good but
>> the slave for all these zone don't.
>> The startup takes about an hour in which the nsd answers to all requests
>> with servfail instead of refusing the connection.
> The startup is slow for both the master and the slave?
no the master starts up within few seconds.
Only the slave configurated server is so slow.

>> In this time it is
>> fetching all serial from the master according to some straces I made to
>> the master process. But the master process keeps consuming 100% CPU time
>> after that. Here is a short strace clip of what it is doing:
> When the master is at 100% CPU, does it still answer queries? (And does
> the slave answer any queries at all?)
I have taken a look.
The first hour or so the slave answers with servfail which is annoying
too I think.. would it not be better if it were refusing the connection
instead ?

After it seems to have finished the first run of serial syncing (I dont
get any new XFER notices in the logfile) It answers on request with the
correct informations but still is at 100% CPU load.

> Can you share some info about hardware setup and memory usage
> statistics, etc?


here some infos:


CPU : Intel(R) Core(TM)2 CPU          6300  @ 1.86GHz (dual core)
MemTotal:      2046920 kB
OS: Linux / Fedora Core6 x86_64
Kernel: 2.6.20-1.2944.fc6 SMP
DNS: 3.0.5 - compiled from official sources.

Mem:   2046920k total,  1760232k used,    28668k free,   166768k buffers
Swap:  1052248k total,     5836k used,  1046412k free,   916348k cached


CPU      : Intel(R) Xeon(R) CPU            5110  @ 1.60GHz (dual core)
MemTotal:      1034120 kB
OS: Linux / Fedora Core7 x86_64
Kernel: 2.6.21-1.3228.fc7 SMP
DNS: 3.0.5 - compiled from official sources.

Mem:   1034120k total,  1013440k used,    20680k free,   195392k buffers
Swap:  1052152k total,       68k used,  1052084k free,   305696k cached


Best regards,
Jan Boysen

Servage.net Web Hosting
Im Grund 9 - DE-24939 Flensburg
janboysen at servage.net

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