[cups] cups-lpd performance and scalability?

[Michael Sweet]

Tim,

We've addressed the major, easy-to-fix performance issues with cups-lpd, but it is still run for every connection/request made by a client, and it is still LPD - no security, extremely limited functionality and error reporting, etc.

It works, but we don't recommend using it when you need to support large numbers of simultaneous clients because it can very easily bring your server to its knees...


> On Aug 22, 2015, at 7:32 PM, Tim Mooney <Tim.Mooney at ndsu.edu> wrote:
> 
> 
> All-
> 
> I've downloaded the cups mailing list archives and spent quite a bit of
> time grepping them for anything related to cups-lpd, but I don't see where
> the question I have about cups-lpd scalability has been addressed before.
> 
> Because of the problems we've run into with Macs running Yosemite not
> being able to submit print jobs to our cups 1.3.7 print server via IPP,
> as described in these threads:
> 
>        http://www.cups.org/pipermail/cups/2015-August/027009.html
>        http://www.cups.org/pipermail/cups/2015-August/027012.html
> 
> We're therefore exploring enabling cups-lpd, so Macs and any other systems
> that can't do IPP 1.1 can submit print jobs to our cups 1.3.7 server.
> 
> The cups-lpd PERFORMANCE section has some pretty dire warnings about
> cups-lpd not scaling, though.  However, web searches I've done for
> "cups-lpd performance" have turned up
> 
>        https://bugzilla.redhat.com/show_bug.cgi?id=132949
> 
> which leads to this CUPS STR:
> 
>        http://www.cups.org/str.php?L804
> 
> That implies that a lot of the original cups-lpd performance issues were
> resolved in the 1.2 series when cupsGetDests() was improved.
> 
> Does that mean that the performance warnings in the cups-lpd man page
> are (somewhat) out of date?
> 
> Does anyone have any idea how cups-lpd scales, when used in a mixed
> IPP and LPD protocol environment?  We've converted our Windows labs to
> use IPP exclusively, so the majority of jobs submitted to our print server
> would be via IPP.  If cups-lpd is still a poor performer, though, we don't
> want to enable it and cause problems for IPP job submittal too.
> 
> Thanks much for any information you can provide!
> 
> Tim
> -- 
> Tim Mooney                                             Tim.Mooney at ndsu.edu
> Enterprise Computing & Infrastructure                  701-231-1076 (Voice)
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_________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair