selecttest tool

[Walter]

JINMEI Tatuya / 神明達哉 wrote:
> I have a couple of suggestions:
>
> 1. you should specify a larger max-cache-size in named.conf.  the
>    default size of 9.5.0 (32MB) is normally too conservative for a
>    busy server with many clients, reducing cache hit rate and making
>    the server busier, and possibly triggering subsequent performance
>    troubles as a result.
> 2. #1 may be sufficient for you, but you may also want to raise
>    recursive-clients (whose default is 1000) to some reasonable large
>    value (e.g., 10000).  I suspect the primary reason for the SERVFAIL
>    in your case is that the server hits the recursive-clients quota.
>    I suspect the server left warning messages like ""no more recursive
>    clients: ...".  Raising recursive-clients will at least solve this
>    issue.
>
>
>   
Jinmei,

Based on your above sugestions, I did the following:
1) set my max-cache-size to 320MB  (I thought ten times the default 
would be ok - this box has 2gb or ram)
2) set my recursive-clients to 10,000

Everything rocked along fine for about 12 hours.  This morning (while I 
was out of town), I received calls that dns queries were failing.  When 
I got back, I see transfer errors in the logs for the time period that 
it seemed to be failing.  This is what was appended to the end of the 
transfer errors:

failed setting up socket: not enough free resources

Any ideas?  I know you probably need more info. than the above.  This 
server is running RHEL5 and I am using the RHEL bind rpm 
(bind-9.3.4-6.0.2.P1.el5_2).  Let me know what other info. you need.  If 
it happens again, I will send output from rndc status.

Thanks,
Walter