[Samba] Performance issue on AIX when deleting files inadirectory with a large number of files

[William Jojo]

----- Original Message ----- 
From: "Jeremy Allison" <jra at samba.org>
To: "Jeremy Allison" <jra at samba.org>
Cc: <samba at lists.samba.org>; "William Jojo" <jojowil at hvcc.edu>;
<jojowil at samba.org>
Sent: Friday, May 12, 2006 7:06 PM
Subject: Re: [Samba] Performance issue on AIX when deleting files
inadirectory with a large number of files


> On Thu, May 11, 2006 at 04:06:37PM -0700, Jeremy Allison wrote:
> > On Thu, May 11, 2006 at 03:54:17PM -0700, Jeremy Allison wrote:
> > >
> > > Do you see the change notify replies happening followed by the
> > > change notify setups ? I bet I know what it is....
> > >
> > > Because AIX doesn't have kernel change notify when the change
> > > notify setup comes (which happens after every delete) it causes a
> > > directory rescan at that point - after *each* delete !
> >
> > I think I can code around this. The key is to ensure that
> > setting "change notify timeout" to zero turns off change
> > notify except for renames and deletes. Also make it a per-share
> > parameter so it can be set to zero for "large" directories...
> >
> > Give me a day or so on this.
>
> Ok - here is the patch. Bill - if you could test this on
> AIX by setting the (now per-share) parameter :
>
> "change notify timeout = 0"
>

Thanks Jeremy! I should have an answer for you on Monday morning.

> on the share definition that holds a large number of files,
> you might find a speed up. I can see the effect it has here
> when I disable the kernel and FAM based change notify.
>

You know, I was trying to manufacture a way to do this with DMAPI (which is
supported on JFS2) and set an event on {postcreate, postdelete, postrename}
and check the errno value for success, but there seems to be absolutely no
way to get the lib to do signalling. It appears to be a poll/select API.
Bummer....I wish IBM would put some of these cool Linux-only goodies in
their FS.


Cheers,

Bill


> Jeremy.
>


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