How to speed up cups

Michael Sweet mike at
Fri Jul 23 07:16:03 PDT 2004

df at wrote:
> Hello,
> we are currently evaluating CUPS as replacement for our AIX printing
> system. It seems to work so far...
> But if the machine get's loaded with round about 2000 Jobs CUPS seems
> to work only with itself, and the throughput of printjobs goes
> heavily down.

Have you tuned the MaxJobs and FilterLimit settings?  The
defaults do not limit the number of print jobs that are
processed at the same time, which can bog a server down quite
easily if you have a lot of non-PS printers.

> We are using Redhat Enterprise Server 3.0 with the latest CUPS
> version that comes with it (i have no access to the machine right
> now, so I can't tell you the exact version).

Probably 1.1.17, which is 1.5 years old.

> Are there any ideas why this breakdown happens?
> Are there any experiences how many printqueues cups can handle (we
> have round about 6000 printers out there)?

We regularly test with 10k printers, and if you have an appropriately
configured system (many processors and lots of RAM and disk) then
things will work fairly well.

What kind of server are you using?

One place to look: LPD client configurations do not scale!  LPD
support in CUPS is provided by an (x)inetd-spawned process for
each connection, and each LPD mini-daemon has to open a local
connection to the CUPS server (cupsd) to do its work.  While we
will continue to tune the cups-lpd program, we do not recommend
using LPD unless you absolutely have to...

Michael Sweet, Easy Software Products           mike at easysw dot com
Printing Software for UNIX             

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