CUPS, AIX, and IPv6 - an FYI

[angelb]

> > For those running CUPS in AIX environment, if you're not already aware,
> > AIX by default, uses IPv6. I'm not sure when IBM made this change but
> > it's effective in 5.2.
> >
> > Disabling IPv6 in AIX resolves the response time delay by eliminating
> > the need for the request to move too high up the DNS chain for resolution and speed up the request to the next available server should
> > the first DNS server is non-responsive.
> >
> > The result -
> >
> > From this: (IPv6 enabled and first DNS server down)
> >
> >      # timex lpr -Pricoh ti01-1.txt
> >      real 113.72
> >      user 0.57
> >      sys  0.02
> >
> >
> > To this: (IPv6 disabled and first DNS server down)
> >
> >     # timex lpr -Pricoh ti01-1.txt
> >     real 3.67
> >     user 0.58
> >     sys  0.03
> >
> >
> > The change- /etc/netsvc.conf
> >
> > 	from: hosts=local,bind
> >
> > 	  to: hosts=local,bind4
> >
> > In fact, to disable IPV6, you can put any (alpha/num)characters after
> > the word "bind" except for the number "6", and it will resolve to IPV4.
> >
> > No downtime or refresh of any kind is required. Immediate performance
> > increase.
>
>
> Angel -
>
> I am seeing poor performance printing under AIX as well.  I tried the solution you suggested above, but the real time always remains around 30 seconds.  Is there anywhere else you suggest I should look?
>
> Also, did you compile cups yourself or use a binary from somewhere?  We are running 1.2.23 compiled ourselves with no options except the prefix.
>
>
> Thanks,
> Amy

You may also want to test RES_TIMEOUT and RES_RETRY. If you're having
some kind of resolution issue, the RES_ can potentialy affect your
response time. I would set them to RES_TIMEOUT=1 and RES_RETRY=1. You
can research what these values are at your convenience.

You might also want to check your ulimit settings. Make sure the
setting can accomodate the number of printer queues you have. Our
default setting was set at 2000 while the number of printer queues we
have was over 2600. When a client submitted a printjob, it took an
extra 5-10seconds longer before it left the client. Once I've changed
the ulimit to a higher value, client response time went back to normal.

We use a binary provided by our software packager.

Good luck.