HOW-TO: Increase performance on ext3 with dir_index

[Lovechild]

dir_index is a hashed b-tree implementation for ext3, it's riskfree (Fedora has shipped several releases defaulting to it without incident), and adds a bit of performance to your filesystem.

to update an existing partitions:
0) open a terminal or enter cli
1) sudo tune2fs -O dir_index /dev/hdXY (where X indicates device, normally a and Y indicates partition, normally 1)
2a) sudo updatedb
alternatively, unmount and do
2b) sudo e2fsck -D /dev/hdXY

Wasn't that easy?

[Kyral]

Cool. I don't knwo if it WORKED, but it hasn't broken my system yet (Then again, I don't know how to tell if it worked )

[henriquemaia]

Is there a way to measure the perfomance gain?

Thanks a lot, though.

[Moobert]

Originally Posted by henriquemaia Is there a way to measure the perfomance gain? Thanks a lot, though.

sudo hdparm -Tt /dev/hdX

may do the trick

[Lovechild]

First, I'm sorry I forgot to mention

sudo tune2fs -l /dev/hdXY | grep dir_index

will show if the given partition has dir_index enabled.

Secondly, to benchmark I would use bonnie++

-edit-

I filed a bug with Ubuntu to have dir_index considered as the new default for Breezy, let's see what they have to say - bug 11284 for those interested.

[dresnu]

I get a segmentation fault when doing sudo tune2fs -O dir_index /dev/hdXY...

[dresnu]

ow! and yes I changed the X and Y to the right values
lol

[Hikaru79]

Is the tune2fs part supposed to take only a fraction of a second to complete? I was expecting something more drawn-out

[Schuttwegraeumer]

Originally Posted by Lovechild dir_index is a hashed b-tree implementation for ext3, it's riskfree (Fedora has shipped several releases defaulting to it without incident), and adds a bit of performance to your filesystem. to update an existing partitions: 0) open a terminal or enter cli 1) sudo tune2fs -O dir_index /dev/hdXY (where X indicates device, normally a and Y indicates partition, normally 1) 2a) sudo updatedb alternatively, unmount and do 2b) sudo e2fsck -D /dev/hdXY Wasn't that easy?

How can I acitivate B*trees on a ext3 on a LVM Set?
This index is not setable in the aditional settings for the FS in the alternate install programm.

Can I do point 1 and 2a without unmounting?
2b is a alternative for what? Only the ubdatedb or point 1 and 2b?

[Schuttwegraeumer]

The -D option in the e2fsck command is in the man page of Ubuntu, but not in the man page of my Knoppix from 2007-01-04.
Since which version is the optimisation includet?