[ANNOUNCEMENT] TEST RELEASE: Cygwin 2.3.0-0.4

Corinna Vinschen corinna-cygwin@cygwin.com
Mon Oct 26 11:13:00 GMT 2015


On Oct 23 14:01, Achim Gratz wrote:
> Corinna Vinschen <corinna-cygwin <at> cygwin.com> writes:
> > There's, as usual, a downside: AuthZ leans a bit to the slow side.
> 
> It's not too bad, as long as your network connection is fast (and fast means
> short roundtrip time for an AD query).  If I take each page fault as
> reported by time as a proxy for an AD access, then it needs about three
> times more roundtrips to the AD.
> 
> On a server with almost perfect connectivity to the AD that increases the
> wall-time of listing a very large directory with directories/files from many
> users (about a quarter of all users in the AD, and not all from the local
> domain) from 8 to 10 minutes.  The CPU time as well as the network traffic
> is neglible in both cases.
> 
> On my local laptop things look a bit different, a small ~5% subset of the
> test above goes from 20s to 200s and a different larger ~10% subset from 50s
> to 500s.

Erm, really?  I tested this locally with a directory with hundreds
of files, each of which belonged to another user or group, and that
resulted in a 25% slowdown.  Not 1000%.  Oh boy.

> While that hurts, the more usual case with many files from the
> same user doesn't feel any slower at the moment.  The access through VPN
> will be interesting, though...

Did you try this in the meantime?

Given the above result, I'm wondering if we can afford using AuthZ at
all.  OTOH I don't see any other way to get the correct POSIX permissions
from a non-Cygwin ACL :(


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat
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