misc/93378: Slow data transfer in Postfix and Cyrus IMAP (problem fix known)

[Juris Orlovs]

>Number:         93378
>Category:       misc
>Synopsis:       Slow data transfer in Postfix and Cyrus IMAP (problem fix known)
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Feb 15 09:20:03 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Juris Orlovs
>Release:        6.0
>Organization:
>Environment:
FreeBSD mx.test.lv 6.0-RELEASE FreeBSD 6.0-RELEASE #0: Sat Jan 21 18:50:10 EET 2006     root at mx.test.lv:/usr/src/sys/i386/compile/SMP-686  i386
      
>Description:
There is a problem with Postfix (2.2.8; 2.3-20060112) and Cyrus IMAP (2.3.1) (installed from ports)

With Postfix on FreeBSD 6.0, transferring of messages using SMTP is slow, aproximately 7MB in 20 seconds on direct 100MBit/s link.

In Cyrus IMAP there is a issue with message writing to IMAP folders. Reading of 8MB message takes a bit less than a second, but in that time 8MB message write to IMAP folder over 100Mbit/s connection takes ~7 seconds. If writing many small messages to imap folder (~1KB in size) then average transfer rate of them is ~10 messages per second.

Hardware: (2x 3GHx Xeon, 2GB RAM, Adaptec 2410SA, 2x WD RAPTOR 74GB, 2x SEAGATE 300GB, Mainboard - Intel SE7520BD2)

For example, there is no such problems with FTP.
>How-To-Repeat:

>Fix:
"sysctl -w net.inet.tcp.delayed_ack=0" fixes mentioned problems with data transfer
>Release-Note:
>Audit-Trail:
>Unformatted: