2 min booting time with raid, WHY???

ekj · 04-16-2007, 07:25 AM

I've got four software raid volumes consisting of four 400 GB sata disks. They're working fine except for one thing - the booting time. The booting procedure takes over two minutes! (from when I'm leaving LILO to when I'm totally logged in, I'm using automatic login). Out of these two minutes, half the time (63 seconds) are spent to do something with the biggest raid volume.

These are my raid volumes:

Code:

device     size    raid type  file system  mounting point
======     ====    =========  ===========  ==============
/dev/md0    94 MB  raid1      reiserfs     /boot
/dev/md1    22 GB  raid5      reiserfs     /
/dev/md2   3.9 GB  raid5      swap         swap
/dev/md3   1.1 TB  raid5      reiserfs     /files

During boot these lines are printed to screen:

Code:

Filesystem is clean
Replaying journal..
Reiserfs journal '/dev/md3' in blocks [18..8211]: 0 transactions replayed

Then the computer performs the check (or whatever it is) of /dev/md3 which takes 63 seconds. Then the following line is printed and the booting continues:

Code:

Checking internal tree..finished

This procedure is performed for all raid volumes except for the swap volume, but the time spent on the other volumes are negligible. So md3 is the only one taking time, but I guess that is because it is slightly bigger than the other ones ;-)

It seems stupid to require 2 minutes for a raid system to boot... So:

What's my computer doing during these 63 seconds?
Is it necessary?

kilgoretrout · 04-16-2007, 08:16 AM

Reiserfs is known to take a long time to mount on large partitions and the larger the partition, the longer it takes. See this guy's experience with large reiserfs partitions:

http://kerneltrap.org/node/6089

If you could change to ext3, you would probably see a significant speedup. From the above article, there appear to be some kernel patches in the 2.6.19 kernels to help remedy this problem.

Quakeboy02 · 04-16-2007, 03:33 PM

There is also the issue that Reiser is in prison, so, where are any future updates going to come from?

ekj · 04-17-2007, 12:38 PM

When I installed my system I chose reiserfs without any specific reason, it was default so I thought it was more modern than ext3. Now I've done some researching, and I concluded that ext3 seems to be the better one.

Anyway, now I have ext3 on /dev/md3, and the booting time is reduced by a minute! Yihaa!!!

But for the other volumes I think I'll keep reiserfs for a while, because the benefit would only be 2-3 seconds. And I don't figure how to change from reiserfs to ext3 on my root partition without having to reinstall my system...