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    SubjectRe: [BK PATCH 1/4] fix NGROUPS hard limit (resend)
    >>>>> "Jesse" == Jesse Pollard <pollard@admin.navo.hpc.mil> writes:

    Jesse> On Tuesday 22 October 2002 12:37 pm, Tim Hockin wrote:
    >> Alan Cox wrote:
    >> > On Tue, 2002-10-22 at 18:26, Tim Hockin wrote:
    >> >>Alan Cox wrote:
    >> >>>Ok sanity check time. Why do you need qsort and bsearch for this kind of
    >> >>>thing. Just how many groups do you plan to support ?
    >> >>
    >> >>Unlimited - we've tested with tens of thousands.
    >> >
    >> > Now how about the real world requirements ?
    >>
    >> Those were real world requirements - we got the number 10,000 from our
    >> product management, which (presumably) spoke with customers. On the
    >> hosting systems, it is really possible to have thousands of virtual sites.
    >>
    >> Now, I don't much care if you want it to be a linear search, and I'll
    >> revert it, if needed, but qsort() is already in in XFS specific code,
    >> and bsearch is small. It doesn't negatively impact any fast path, and
    >> provides better behavior for the crazies that really want 10,000 groups.
    >>
    >> Tim

    Jesse> Does it actually work with NFS???? or any networked file
    Jesse> system? Most of them limit ngroups to 16 to 32, and cannot
    Jesse> send any data if there is an overflow, since that overflow
    Jesse> would replace all of the data you try to send/recieve...

    Jesse> And I really doubt that anybody has 10000 unique groups (or
    Jesse> even close to that) running under any system. The center I'm at
    Jesse> has some of the largest UNIX systems ever made, and there are
    Jesse> only about 600 unique groups over the entire center. The
    Jesse> largest number of groups a user can be in is 32. And nobody
    Jesse> even comes close.

    $ ypcat group | wc -l
    9527

    $ ypcat passwd | wc -l
    62076

    Yes, we're insane :-)

    OTOH, we use AFS and PTS groups, because Unix groups don't scale. And
    we would not use the ngroups mechanism in Linux even if it did,
    because we need to inter-operate with Solaris.

    Cheers, Hildo
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