On 1/18/2012 3:26 PM, Stan Hoeppner wrote: > On 1/18/2012 4:46 AM, Konrad Rzepecki wrote:
>> I don't know why it take some much time, but it cannot be disabled >> (fsync) in postfix due to delivery guarantee. However, my mails (those >> ones) are not very important, and lost some of them is not a problem, so >> such option will be useful for me. Best in some >> "recipient|sender_disable_fsync_maps" fashion. > > fsync isn't your (only) problem if batch queuing 15K messages takes an > hour+ with an 8 disk RAID10 w/4 spindles of IOPS throughput. Even at > 7.2K RPM each disk should be able to fsync at least 50 small (4KB-16KB) > msgs/sec, unless they are something huge like 1MB newsletters with > attachments or some such. > > 50*4*3600 = 720,000 msgs/hour > > Likewise, at 200 msgs/sec fsync'd: > > 15,000/200 = 75 seconds To demonstrate that fsync alone shouldn't be a factor here, I just used smtp-source to send 15K msgs of 2KB size to a local test account, using a single feeder thread. Both the postfix queue and the target mbox mail file reside on a 35GB EXT2 (yes, EXT2) filesystem on a single 7.2K Western Digital 500GB single platter SATA drive. Writes to the queue were in competition with Dovecot deliver appending the msgs to the mbox file during the entire run. $ time smtp-source -s 1 -l 2048 -m 15000 -c -f * -t * localhost:10125 15000 real 6m29.462s user 0m15.325s sys 0m23.709s Queuing 15K messages took 6 minutes 30 seconds on a single 7.2K drive, again while competing with the delivery agent for spindle time. And this performance is from a 12 year old box. Your quad core 8 drive RAID10 box should be able to queue at least 60K msgs with your injection method in the same amount of time. Test system specifications: Abit BP6, 2xCeleron 550, 384MB PC100, SiI3512 SATA PCI, 1xWD5000AAKS Vanilla kernel 2.6.38.6, Debian 6.0.3, Postfix 2.8.3, Dovecot 1.2.15 elevator=deadline min_free_kbytes=8192 vfs_cache_pressure=100 If your kernel is using CFQ you may want to try deadline. But that alone isn't going to fix a 10x performance deficit. You've probably got multiple factors degrading performance. -- Stan
