[imp] Slowness with big mailboxes _Sticky Bit

Peter Farrow PeterF@3d-computers.co.uk
Tue, 2 Oct 2001 15:02:14 +0100
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When the sticky bit (t) is turned on for a directory users can have read
and/or write permissions for that directory, but they can only remove or
rename files that they own. The sticky bit on a file tells the operating
system that the file will be executed frequently. Files like this are kept
in swap space even when they aren't being executed. Although this takes up
swap space it greatly reduces the time it takes to execute the program.
Programs such as vi have the sticky bit turned on by default.

Peter Farrow 
peterf@3d-computers.co.uk
Technical Director
3D computer Systems
01249 460766
01249 460583 (fax)

www.3d-computers.co.uk
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-----Original Message-----
From: Chip Mefford [mailto:cmefford@avwashington.com]
Sent: 02 October 2001 14:27
To: imp@lists.horde.org
Subject: Re: [imp] Slowness with big mailboxes


On 2001.10.02 05:47 Alex Leverington wrote:
> 
> I have found that 'chmod +t' the your mail direcotry in
> spool *greatly* 
> improves speed (ex: chmod +t /var/spool/mail)
> 
> I did this and it improved performance drastically. I'm
> not sure what it does 
> but I read it on a post once. I'm guess it sets some type
> of access priority or 
> does read-ahead caching or something. Nonetheless, it
> worked for me.
> 
> Regards,
> 
> Alex Leverington

I'm confused, 
Some of the older documentation I have says the t switch
sets the "sticky" bit, other docs state that the t switch
saves the program text on swap device. 

I expect it is the latter operation that is at play
here, but I don't see why this would be a great idea
for mail? 

what exactly does the t switch do? If /var/spool/mail
is set to save text on swap, and swap is smaller
than a users mailbox, which is at least conceivable,
users being what they are, wouldn't that turn into a
real issue? 


 
> 
> Quoting Peter Farrow <PeterF@3d-computers.co.uk>:
> 
> > Dear Paul,
> > 
> > I have set imp up on a Red Hat Linux machine (7.0 and
> 7.1) and found the
> > following information:
> > 
> > On Red Hat 7.0 running on a single PIII 650 machine with
> 256 Megs of RAM
> > takes a long time (>1 Min)to open a mailbox with 3000 or
> so messages in it,
> > 
> > 
> > On Red Hat 7.1 running on a Dual Celeron 366 machine
> with 512Megs RAM it
> > takes around 10 seconds to do the same thing.
> > 
> > So its either: Red Hat 7.1, RAM or twin CPUs that makes
> the difference for
> > me.
> > 
> > Notably, when connecting  to a Micro$oft Exchange server
> it takes about 10x
> > as long than connecting to a real mail server running
> Solaris on an E4000
> > machine, even when the Mailboxes are of comparable
> complexity.
> > 
> > I know this isn't much help, but it gives you somewhere
> to start!  An Imap
> > proxy moves the delay downstream and may not help as
> much as you need.
> > 
> > Regards
> > 
> > Peter Farrow 
> > peterf@3d-computers.co.uk
> > Technical Director
> > 3D computer Systems
> > 
> > www.3d-computers.co.uk
> > -----Original Message-----
> > From: Paul Fielding [mailto:paul@mainland.ca]
> > Sent: 01 October 2001 21:07
> > To: imp@lists.horde.org
> > Subject: Re: [imp] Slowness with big mailboxes
> > 
> > 
> > Quoting Jon Parise <jon@horde.org>:
> > 
> > > There's really no way around it at the moment.  You
> might try
> > > looking at an IMAP proxy, such as Perdition:
> > 
> > But I guess my question is, no way around what?
> > 
> > It seems to me that it isn't just an 'accepted problem'.
>  I'm experiencing
> > a
> > 
> > slow down on big mailboxes, other people aren't. 
> Obviously this means that
> > 
> > there should be something I can change in my system that
> should remedy the 
> > situation.  Perhaps an OS issue, perhaps an IMP issue,
> perhaps my hardware 
> > simply isn't beefy enough and I need to upgrade it.
> (Just how much
> > horsepower 
> > does IMP need to connect to a mailserver and server out
> big mailboxes
> > quickly? 
> > Mine's a Pentium class box).
> > 
> > <shrug>  I'm just trying to understand what the problem
> actually is...
> > 
> > regards,
> > 
> > Paul
> > 
> > -- 
> > IMP mailing list: http://horde.org/imp/
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> > Frequently Asked Questions: http://horde.org/faq/
> > To unsubscribe, mail: imp-unsubscribe@lists.horde.org
> > 
> > 
> > -- 
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> > 
> 
> 
> 
> 
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>From chuck@horde.org Date: Tue,  2 Oct 2001 10:49:30 -0400
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Subject: Re: [imp] Attachments Size

Quoting Augusto Farina <augusto@funcitec.rct-sc.br>:

> How can I define an attachment size ? I´m having problems with big files...
> I got this message:
> 
> Warning: Undefined variable: attachments_size 
> in /home/webmail/horde/imp/compose.php3 on line 930

What browser are you using? What version of IMP?

-chuck

--
Charles Hagenbuch, <chuck@horde.org>
"What was and what may be lie, like children whose faces we cannot see, in the 
arms of silence. All we ever have is here, now." - Ursula K. Le Guin


>From chuck@horde.org Date: Tue,  2 Oct 2001 10:51:25 -0400
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From: Chuck Hagenbuch <chuck@horde.org>
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Subject: RE: [imp] Slowness with big mailboxes

Quoting Paul Fielding <paul@mainland.ca>:

> With IMP, on a small mailbox (ie. under 30-40 messages), it is also snappy.  
> But with a large mailbox (100+ messages) it takes upwards of 1 minute to get 
> the mailbox open.  And this 1 minute recurs *ever* time you flip back to the 
> inbox or make a change (delete a file, expunge, etc).  It makes it pretty much
> unusable in these scenarios.

For the record, I use IMP to handle pretty much all of my email, and that 
includes on my INBOX which routinely grows to 200+ messages, and it's nice and 
zippy...

-chuck

--
Charles Hagenbuch, <chuck@horde.org>
"What was and what may be lie, like children whose faces we cannot see, in the 
arms of silence. All we ever have is here, now." - Ursula K. Le Guin
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