Settings for File Descriptors

Hayward, Bruce Bruce.Hayward at mtsallstream.com
Fri Mar 6 19:27:16 UTC 2009


Thanks much

Email to bruce.hayward at mtsallstream.com


> -----Original Message-----
> From: Chris Thompson [mailto:cet1 at hermes.cam.ac.uk] On Behalf 
> Of Chris Thompson
> Sent: Friday, March 06, 2009 12:12 PM
> To: Hayward, Bruce
> Cc: Bind Users Mailing List
> Subject: Re: Settings for File Descriptors
> 
> On Mar 6 2009, Hayward, Bruce wrote:
> 
> >I am trying to understand file descriptors with bind in 
> mind, and what 
> >they should be set at in conjunction with the OS.
> > 
> >We are running 9.5.1 P1 on Solaris 10 (patched up), which is 
> basically 
> >all that is on each server.
> > 
> >Some questions:
> > 
> >1) Is there a recommended setting (number of FDs)?
> 
> BIND will set the file descriptor resource limit to 
> "unlimited" when it starts up, unless you tell it not to in 
> the "options" setting.
> Just forget about it.
> 
> >2) Better to set this at the kernal level with the set rlimit, or a 
> >compile option with configure, or both
> 
> This doesn't apply to BIND (see above) but I think it foolish 
> to mess around with /etc/system to change resource limits for 
> all processes, when you can easily use a targetted "ulimit" 
> command in the calling script for the process that actually needs it.
> 
> BIND doesn't have a compile option for this, anyway, AFAIK. 
> Are you confusing this with the FD_SETSIZE value? BIND 
> 9.5.1-P1 on Solaris will not be using select(3c) anyway, so 
> that isn't an issue.
> 
> >3) Should the number be correlated to the number of 
> recursive clients?
> >4) Different on the auth servers?
> 
> If you did go out of your way to make it other than 
> "unlimited", then yes to both. But don't.
> 
> --
> Chris Thompson
> Email: cet1 at cam.ac.uk
> 



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