[Dovecot] Thunderbird slow in talking with dovecot IMAP AND to sendmail
I'm trying to find out what's causing this slowdown -- it's INTOLERABLE....
over 1 minute and less than 1% done. (400MB file)...
After trying 3 times, I gave up and logged in using X to the server and ran Tbird from there....
Mail sent out in < 1 minute, though the copy to dovecot took about 50% longer.
So...
I looked at the network trace.
and everyfrackin' body was using 4K packet sizes (at the application level!, the window size on TCP was over 64K...but no one was using it)....especially galling with my network's MTU at 9K, BTW, because small packets are really bad on a 1Gb network.
sendmail -- 4K, dovecot /ssl, 4K...
wazzup .. is t-bird forcing this, or is there some ssl requirement?
but it can't just be ssl -- as it's talking to sendmail on port 25 unencrypted (it's a local net anyway)...
I could see the entire binary going out in text form...
1 line at a time...a "C" line in sendmail, with lens of 4096...is that some max?
I don't see it in the sendmail.cf files...wanted to see if anyone knew of dovecot restrictions that might limit packets to 4k, before I lamblasted the thunderbird people for another act of mindless stupidity (the first being when they decided to cache all your IMAP store on every local client in the client's ROAMING profile...*brilliant*!!!...
sides, if I wanted it on local I would have set 'store on local', but in TB3, they know better and change that for me...
Something about them being too stupid to use indexing and searching on an imap server? Maybe I just imagined hearing that...
On 2011-10-25 6:14 AM, Linda Walsh <dovecot@tlinx.org> wrote:
and everyfrackin' body was using 4K packet sizes (at the application level!, the window size on TCP was over 64K...but no one was using it)....especially galling with my network's MTU at 9K, BTW, because small packets are really bad on a 1Gb network.
sendmail -- 4K, dovecot /ssl, 4K...
wazzup .. is t-bird forcing this,
If I'm not mistaken, yes, this is (or could be) a TBird problem... I can't find the bug report where this was discussed, but I distinctly remember one of the devs commenting on this 4k packet size issue. Apparently it was an intentional change, but he couldn't figure out why.
Fyi, it was discussed in one of the IMAP performance bugs...
--
Best regards,
Charles
Charles Marcus wrote:
On 2011-10-25 6:14 AM, Linda Walsh <dovecot@tlinx.org> wrote:
and everyfrackin' body was using 4K packet sizes (at the application level!, the window size on TCP was over 64K...but no one was using it)....especially galling with my network's MTU at 9K, BTW, because small packets are really bad on a 1Gb network.
sendmail -- 4K, dovecot /ssl, 4K...
wazzup .. is t-bird forcing this,
If I'm not mistaken, yes, this is (or could be) a TBird problem... I can't find the bug report where this was discussed, but I distinctly remember one of the devs commenting on this 4k packet size issue. Apparently it was an intentional change, but he couldn't figure out why.
Fyi, it was discussed in one of the IMAP performance bugs...
Thanks for the lead...will check it out.The problem with the Tbird (and FF) is that design for home users with dialup connections, so if you have a home network and run IMAP @home, all their tuning goes out the window -- and they don't make it configurable.
I had to go to a 9K packet size on 1Gb ethernet to get close to full bandwitch usage (and then it is a large effort with a windows client)...and that's down at layer 2? FF IMAP is at layer 5? ... the latency is insane at that point.
Alot of companies aren't real bright when it comes to storing files locally -- instead of 'local' they almost always use the 'roaming' profile...Cuprits: TB@4G, Adobe@2.5G, XBMC ~1-2G. Adobe's great -- most of that 2.5G are the product helpfiles which you don't get when you install -- they are d/led later and thus stored in your roaming profile. Each user gets their own copy of the help material...
Of course good thing they got rid of customer input for product design and got rid of 'usability studies'... those things always caused problems. Like MS removing the start bar in Win8 cause users don't want it? Huh? or Cocacola switching to 'newCoke, then having to revert due to outcry...because Coke drinkers didn't want another pepsi knockoff.
Baka!
On 25/10/2011 11:14, Linda Walsh wrote:
I'm trying to find out what's causing this slowdown -- it's INTOLERABLE....
over 1 minute and less than 1% done. (400MB file)...
After trying 3 times, I gave up and logged in using X to the server and ran Tbird from there....
Mail sent out in < 1 minute, though the copy to dovecot took about 50% longer.
So...
I looked at the network trace.
and everyfrackin' body was using 4K packet sizes (at the application level!, the window size on TCP was over 64K...but no one was using it)....especially galling with my network's MTU at 9K, BTW, because small packets are really bad on a 1Gb network.
Although larger packets might be helpful, I don't see that you shouldn't be getting much faster speed without it? Even the 64K window, whilst it looks too small, might be ok if your ping times are very low?
Something else is limiting your performance I think?
Ed W
participants (3)
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Charles Marcus
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Ed W
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Linda Walsh