Blubber

158 reputation

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	158 reputation	bio	website		visits	member for	1 year, 2 months
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Mar 27	revised	PostgreSQL slow commit performance added 360 characters in body
Mar 27	revised	PostgreSQL slow commit performance added 2049 characters in body
Mar 27	comment	PostgreSQL slow commit performance I have amended my original question with additional information about mount options and partition alignment.
Mar 27	revised	PostgreSQL slow commit performance added 1624 characters in body
Mar 27	comment	PostgreSQL slow commit performance I ran bonnie++ which shows good performance (as good as you'd expect from regular sata disks). Also, the partitions are aligned. When I ran pg_test_fsync the first time it was on a VM. Then I ran it on the actual hardware, after shutting down every other process (including VMs). The performance was slightly better, around 40 ops/sec, which is still deplorable. I'm going to run some more tests, on separate partitions if I got the time today. Thanks for all the suggestions.
Mar 25	comment	PostgreSQL slow commit performance Just checked, the firmware on both disks is at the latest version (CC4H).
Mar 25	comment	PostgreSQL slow commit performance I have amended my original question with information about the disk types. In the meantime I tried setting noatime and killed all other processes (when possible) on the machine. This increases the performance two-fold, from extremely bad, to just really bad.
Mar 25	revised	PostgreSQL slow commit performance added 150 characters in body
Mar 25	awarded	Commentator
Mar 25	comment	PostgreSQL slow commit performance The short smart test on both disks revealed no problems, I started long tests on both, and will check the results asap. dmesg and the syslog showed no errors. I checked the partition aligned friday, they are aligned on 4k boundaries, also, the disks use GPT, so fdisk -l doesn't show useful output.
Mar 22	revised	PostgreSQL slow commit performance added 44 characters in body
Mar 22	comment	PostgreSQL slow commit performance I have updated the question with more details about the filesystem and raid config. I understand that this machine is never going to give very good performance in it's current configuration. But the current performance is really bad.
Mar 22	revised	PostgreSQL slow commit performance Formatting
Mar 22	comment	PostgreSQL slow commit performance I tried running pg_test_fsync on my own SSD, and I get comparable performance figures. I know that I could disable sync commits, but the question remains, what is the cause of this problem?
Mar 22	comment	PostgreSQL slow commit performance Yes, but what is causing the bad fsync performance?
Mar 22	revised	PostgreSQL slow commit performance added 75 characters in body
Mar 22	asked	PostgreSQL slow commit performance
Apr 6	awarded	Teacher
Apr 5	answered	FreeBSD network performance fluctuating
Apr 5	revised	FreeBSD network performance fluctuating added 424 characters in body