McEs, A Hacker Life: Linux Tip: tune2fs

Wednesday, February 22, 2006

Linux Tip: tune2fs

Tiny and trivial yet useful tip: By default, ext2 and ext3 filesystems reserve %5 of the capacity of the partition for root, such that if the users fill up the partition, services running as root (as well as commands the root user runs) don't fail right away. You can reclaim that precious %5 on your /home or other user-only partitions by doing tune2fs -m 0 /dev/hdaX.

I have to look around and clean up space on my harddisk every other week, so gained some 2.5GB this way and I'm so happy about it (-:.

(I'm going to open an RFE with Fedora, to not reserve this %5 on /home partition by default. Update: filed here. Update 2: Jeremy Katz comments in the bug that this reserved space is used to avoid fragmentation too. So zero is probably not the best value. Set mine to %1...)

¶ 8:36 PM

Comments:

Don't worget fragmentation.

Using a filesystem with its maximum capacity is likely to seriously harm performance on the long run. One of the reasons for the 5 % reservation is fragmentation control.

# posted by

Anonymous : February 23, 2006 11:58 AM

You might wanna also caution people to NOT run tune2fs on mounted filesystems....!

# posted by

Anonymous : March 23, 2006 8:25 PM

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