[linux-lvm] Poor performance with LVM 1.0.7

[Henric Andersson]

> check the raw performance of one drive involved
> with hdparm -tT ...

Did that, it reported between 27-45MB/s on all drives (ranging from the system harddrive to the LVM
harddrives)

> > After scouring the net for suggestions on how to improve the speed, I came
> > up empty, and thus, I'm writing this email :)
> >
> > Some more facts (more available if needed ;)) about the server:
> >
> > All drives are tuned with 32bit transfers and DMA enabled. I'm running
> > kernel 2.4.22pre2 (gentoo).
>
> just for the fun of doing it, compile vanilla
> 2.4.22 and give it a try ... you could also add

Oki, will try it as soon as I get home.

> the following lvm patch ...
> http://www.13thfloor.at/VServer/patches-2.4.22-p10c17/07_lvm-1.0.7-2.4.21pre5.patch.bz2

Hmm? What does this patch do?

> was the performance you had on your old box higher?
> or did you just expect an increase in speed, which didn't
> happen?

Performance on my old box was lower, so I expected it to increase with my new system. And it did, as
long as I don't serve any files from the volumeset, everything runs just fine (9.5MB/s) but whenever I
try to access files on the LV, I get 4-5MB/s ...

Even tried doing:

time cat "somefile on the LV set" > /dev/null

Which performed equally bad (ie, about 4-5MB/s). Doing the same on the /dev/hda1 drive gives ALOT
better performance (more in the line of what hdparm -Tt reports)

/Henric