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J.D. Bronson | 3 Nov 2002 14:25
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performance under solaris

I recently changed over from qpopper 4.X to popa3d and using the 0.5.9 version.

While it installed just fine and works very well, there is a performance 
issued noted from qpopper TO popa3d.

It is a little hard to describe, but basically when we use qpopper and have 
a sizable mail spool file, it is 'popped' down very fast and continously 
flowing.

However, with popa3d I see pauses (although not of any duration to speak of)
when grabbing this same exact mail spool file.  grab-pause-grab-pause and 
so on...

(I turned off my MTA to make sure this was not an issue)

I was therefore wondering if there are any suggestions with buffer 
adjustments (?) or similar within the params.h file to improve my performance.

I dont have a tremendouse amount of users, but someone noticed this and it 
certainly was reproducable.

Any thoughts?

--

-- 
J.D. Bronson
Aurora Health Care // Information Systems // Milwaukee, WI USA
Office: 414.978.8282 // Fax: 414.328.8282 // Pager: 414.603.8282
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Solar Designer | 3 Nov 2002 20:02
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Re: performance under solaris

On Sun, Nov 03, 2002 at 07:25:09AM -0600, J.D. Bronson wrote:
> It is a little hard to describe, but basically when we use qpopper and have 
> a sizable mail spool file, it is 'popped' down very fast and continously 
> flowing.
> 
> However, with popa3d I see pauses (although not of any duration to speak of)
> when grabbing this same exact mail spool file.  grab-pause-grab-pause and 
> so on...

How long are the pauses?

What network equipment is in use between the server and the client?
What bandwidth?  What client OS?

> I was therefore wondering if there are any suggestions with buffer 
> adjustments (?) or similar within the params.h file to improve my 
> performance.

Well, this sounds like a networking problem, so you may try one of the
following:

1. Investigate and solve it.  tcpdump may be helpful.  You may post
some details in here (but please keep your message size under 10 KB),
such that me or others might be able to help.

2. Try to workaround it by reducing buffer size to be under MTU.  Set
RETR_BUFFER_SIZE to be less than half your MTU, say, to 700 bytes.
(The "less than half" is because content may be at worst doubled by
LF -> CRLF expansion.)
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J.D. Bronson | 3 Nov 2002 20:12
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Re: performance under solaris

At 01:02 PM 11/3/2002, you wrote:
>On Sun, Nov 03, 2002 at 07:25:09AM -0600, J.D. Bronson wrote:
> > It is a little hard to describe, but basically when we use qpopper and 
> have
> > a sizable mail spool file, it is 'popped' down very fast and continously
> > flowing.
> >
> > However, with popa3d I see pauses (although not of any duration to 
> speak of)
> > when grabbing this same exact mail spool file.  grab-pause-grab-pause and
> > so on...
>
>How long are the pauses?

1-2 seconds....enough to be noticed, but not enough to be a problem :-/

>What network equipment is in use between the server and the client?
>What bandwidth?  What client OS?

100MB/FD switches/cards. All on the same LAN segment. Clients run XP Pro.

> > I was therefore wondering if there are any suggestions with buffer
> > adjustments (?) or similar within the params.h file to improve my
> > performance.
>
>Well, this sounds like a networking problem, so you may try one of the
>following:
>
>1. Investigate and solve it.  tcpdump may be helpful.  You may post
>some details in here (but please keep your message size under 10 KB),
(Continue reading)

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Solar Designer | 3 Nov 2002 21:59
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Re: performance under solaris

On Sun, Nov 03, 2002 at 01:12:54PM -0600, J.D. Bronson wrote:
> At 01:02 PM 11/3/2002, you wrote:
> >On Sun, Nov 03, 2002 at 07:25:09AM -0600, J.D. Bronson wrote:
> >> However, with popa3d I see pauses (although not of any duration to 
> >speak of)
> >> when grabbing this same exact mail spool file.  grab-pause-grab-pause and
> >> so on...
> >
> >How long are the pauses?
> 
> 1-2 seconds....enough to be noticed, but not enough to be a problem :-/

This may be caused by dropped packets, 1-2 seconds is what it may take
before a packet is retransmitted on a LAN.

> OTOH, since running spop3d or qpopper result in higher performance, I doubt 
> there is anything on my network that needs fixing......:-/

Wrong conclusion.

Although may turn out to be not network, but network stack configuration
on one of the ends (Solaris?)

I really suggest that you investigate with tcpdump.  It is likely that
you will see retransmits.

> However, I am presuming that these programs make use of something in a 
> different manner than popa3d

Yes.  popa3d sends more data at once to the kernel and thus probably
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Gil Disatnik | 17 Nov 2002 14:20

Mailbox symlink

Hey there,
I am using popa3d that comes with slack-current (0.5.1).

/var/spool/mail/≤username> is in fact a symlink to $HOME/Maildir.

For some reason popa3d doesn't follow symlinks (Tried putting the Maildir 
file there and it worked).
Is there a way around it?

Thanks.

Regards

Gil Disatnik
UNIX system/security administrator.

GibsonLP <at> EFnet

_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
"Windows NT has detected mouse movement, you MUST restart
your computer before the new settings will take effect, [ OK ]"
--------------------------------------------------------------------
Windows is a 32 bit patch to a 16 bit GUI based on a 8 bit operating
system, written for a 4 bit processor by a 2 bit company which can
not stand 1 bit of competition.
-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
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Solar Designer | 17 Nov 2002 14:25
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Re: Mailbox symlink

On Sun, Nov 17, 2002 at 03:20:58PM +0200, Gil Disatnik wrote:

Hi,

> I am using popa3d that comes with slack-current (0.5.1).
> 
> /var/spool/mail/≤username> is in fact a symlink to $HOME/Maildir.

You mean, to $HOME/Mailbox?

Yes, that won't work.  The reason I've added safety checks to popa3d's
mailbox opens is to defeat certain attacks possible specifically when
mailboxes are in user-writable directories (that is, when popa3d is
built with support for $HOME/Mailbox).  One such attack would be
symlinking $HOME/Mailbox to /dev/zero.

You really need to rebuild popa3d with support for $HOME/Mailbox, this
is an option in params.h.

As you're currently using the Slackware package, you need to choose
one of:

1. Modify the Slackware package to build popa3d with this option.

2. Build popa3d manually, install under /usr/local (that's where "make
install" would place it by default) and use that instead of the binary
provided with Slackware.

--

-- 
/sd
(Continue reading)

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Gil Disatnik | 18 Nov 2002 14:34

Re: Mailbox symlink

$HOME/Mailbox, yeah, my mistake.

I'll rebuild the package myself.

Thanks!
At 04:25 PM 11/17/2002 +0300, you wrote:
>On Sun, Nov 17, 2002 at 03:20:58PM +0200, Gil Disatnik wrote:
>
>Hi,
>
> > I am using popa3d that comes with slack-current (0.5.1).
> >
> > /var/spool/mail/≤username> is in fact a symlink to $HOME/Maildir.
>
>You mean, to $HOME/Mailbox?
>
>Yes, that won't work.  The reason I've added safety checks to popa3d's
>mailbox opens is to defeat certain attacks possible specifically when
>mailboxes are in user-writable directories (that is, when popa3d is
>built with support for $HOME/Mailbox).  One such attack would be
>symlinking $HOME/Mailbox to /dev/zero.
>
>You really need to rebuild popa3d with support for $HOME/Mailbox, this
>is an option in params.h.
>
>As you're currently using the Slackware package, you need to choose
>one of:
>
>1. Modify the Slackware package to build popa3d with this option.
>
(Continue reading)

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