The way I understand Postfix's qmgr process to work is that it governs how/if/when to move messages into the active queue for a message to be sent.
For a postfix server that I have under a large mail load load (processes 50k - 100k messages per hour), and operates under a consistent low system load, the qmgr seems to be choking for a set of messages on a domain which I deliver to frequently.
postfix lines look like this:
Nov 19 11:51:06 mailservername postfix/smtp[23395]: 1C0C68A36EA: to=<someaddress@somedomain.com>, relay=somemxrecord.com[111.111.111.111]:25, conn_use=20, delay=6358, delays=0.04/6355/0.73/2.2, dsn=2.0.0, status=sent (250 ok)
IO stat looke like this:
avg-cpu: %user %nice %system %iowait %steal %idle
12.30 0.00 4.42 6.13 0.00 77.16
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 68.43 41.45 53.15 1425781078 1828177680
Feel free to ask for more information and I can provide. Thanks in advance.
