Lesson 3 | Ext2 configuration, part 2 |
Objective | Use tune2fs, dumpe2fs, and debugfs to optimize and configure the ext2 filesystem. |
Red Hat Ext2 File System
Use the
tune2fs command with the
-c
option to reduce the number of system checks. Typically after twenty mounts, an ext2 filesystem gets a forced system check. In the past, this was a wise precaution to fix errors before they affected filesystem performance or availability.
However, large partitions take several minutes to perform a check, which means the filesystem isn't available for use during this time With today's less error-prone hardware, frequent checks are not as necessary. The
tune2fs
command's
-c
option allows you to set the maximum number of mounts, called the
mount count, before a check is enforced. The
e2fsck program
, which normally checks filesystems at boot, will check the actual number of mounts against the
maximum mount count. If the mount count exceeds the maximum, then
e2fsck
will intensively check the filesystem. If any errors were detected, but not automatically corrected, you should use the filesystem debugging utilities outlined below to fix the problems.
tune2fs
Do not use
tune2fs
on a mounted filesystem!
Unmount the filesystem first, then update the parameters. Modifying active filesystems will cause complications, and possibly even the loss of the filesystem.
dumpe2fs and debugfs
If errors were encountered during the e2fsck
check, use the command dumpe2fs
to show the filesystem's state. dumpe2fs
, as the name suggests, provides a dump of information about a filesystem. This information can provide clues as to what the exact problem is, which you will need to correct manually. To use this command, provide the filesystem as its first parameter--for example: dumpe2fs /dev/hda5
. debugfs
provides an interactive, text-based interface that allows you to correct filesystem errors manually. It provides a rich set of examination, diagnostic, and modification commands. Like dumpe2fs
, provide the filesystem to debug as its first parameter, as in debugfs /dev/hda5
.
For more information about ext2fs tools, see the
Question: Enter the command to debug the /dev/hdb2 filesystem.
Answer: debugfs /dev/hdb2
The next lesson discusses the use of the automounter.