mdraid write performance in different kernels up to 3.0, 3.0 shows huge improvement

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




Hello.

I have been running mdraid->cryptsetup/LUKS->lvm->xfs on Ubuntu AMD64 with RAID5 and now RAID6 for quite some time, dating back to 2.6.27. Around 2.6.32 I saw quite a bit of regression in write performance (probably the implementation of barriers), 2.6.35 was acceptable, 2.6.38 was really really bad, and 3.0 is like a rocket. Best of them all.

I'm talking about 10-20x in different in write performance on my workload, in combination with the older kernels throwing me page allocation failures when the write load gets high, and also quite often the machine would just freeze up and had to be rebooted.

With 2.6.38 I was down to 6-10 megabyte/s write speed, whereas 3.0 seem to give me 100+ megabyte/s with the exact same workload, I've seen up to 150 megabyte/s writes at good times. This is on a box with AES-NI, so the crypto is not the limiting factor.

I have from time to time sent out an email regarding my page allocation failures, but never really got any takers on trying to fault find it, my tickets with ubuntu also never got any real attention. I haven't really pushed it super hard with 3.0, but I've thrown loads at it that would make 2.6.38 lock up.

Just wanted to send in this success report that this finally seem to have seen some really nice improvements!

--
Mikael Abrahamsson    email: swmike@xxxxxxxxx

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>


[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]