MAN page from Mandrake Other defrag-0.73-5.i386.rpm

DEFRAG

Section: Maintenance Commands (8)
Updated: Version 0.73 25 Jan 1998
Index

NAME

[ex][2]defrag - defragment file systems.

SYNOPSIS

defrag|edefrag | e2defrag| xdefrag[-Vdnrsv] [-bbad-inode] [-iinode-list] [-p pool-size]/dev/name

DESCRIPTION

Defrag will reorganise data on a minix file system partition in orderto improve the file system's performance.Edefrag is the equivalentprogram for the extended file system.E2defrag in its turn is designed for the second extended file system (versions0.3 onwards). And thexdefragprogram will operate on Xia FS filesystems.

Note that unlike thefsckprogram,defragMUST NOT be run on a mounted file system device (unless invoked withthe-r(readonly) option, which is always safe). Also note that if youdefragment a partition containing a bootable kernel image, you willhave to reinstall the boot loader for that image (since the locationon disk of the image may have changed).

Remember, ifdefragfails to complete for any reason (including power glitches, kernelbugs etc.), you will be left with a terminally sick, and possiblycompletely unreadable, filesystem, so backup any valuable data beforeyou start.

OPTIONS

-V: Supply full version information. If you are sending bug reports,please include this information.
-d: Run in debugging mode. This will not be available if disabled atcompile-time.
-n: No-picture more. Disables a pseudo-graphic picture and runs with anold-style printf output. Note that the picture option requires aproper terminfo database for your terminal, compatible with thencurses package. If the picture option is used,-v and-s options are set automatically. Nevertheless you can increase amount ofinformation output to the status line using several-v switches. This gives you a chance to improve the speed of your reading.
-r: Readonly mode. Defragwill scan the file system and simulate the job of defragmentation, butwill not write to the file system. This can be used for debugging ortesting. It may also be used to find out how much workdefragwill have to do, in order to choose a sensiblepool-size
-s: Summarise file system information anddefragperformance statistics.
-v: Verbose - gives a progress report as defragmentation proceeds. If-vis given twice, then a more detailed report is supplied. The fullestreport, when-vis given three times, also reports the inode prioritylist as it is read.
-b bad-inode: Indicate which inode stores the badblock list on the filesystem beingdefragmented. This should be an inode whose data blocks are all badblocks. The defragmenter will not move these blocks, and will preventany other data from being placed there.
The default for edefrag is-b2, since mkefsalways creates a bad block inode at inode 2. The minix filesystemdoes not have a bad block inode by default, but if you have createdone, supply its inode number with this option.
-i inode-list: As of version 0.4, defraghas a new facility which allows you to specify how to reorganise thedata on your disk. The inode-listis an optional file giving a priority between -100 and 100 to eachinode in the filesystem. Higher priorities will be allocated nearerthe beginning of the disk than lower (more negative) priorities. Twoinodes of equal priority will be allocated in the same sequence theyhad originally on the filesystem, to minimise file movement. Allinodes have a default priority of zero if they are ommitted from thefile or if no-ioption is given.
The file inode-listshould contain a series of lines containing either a single number(which will be interpreted as an inode number), or a number prefixedimmediately by an equals sign (which will be interpreted as a priorityto be applied to the subsequent inode numbers).
-p number: Selects the number of buffers allocated to the defragmenter's bufferpool. These buffers are used when relocating data, so the morebuffers allocated, the more efficient the relocation process. Thenumber you choose will depend on how much physical and virtual memoryyou have available. The default pool size is 512 buffers (equivalentto 512kB of memory used for filesystems with the default 1kB blocksize).

BUGS

Maybe, but then that's why you backed up your data first, isn't it?

AUTHORS

Written by Stephen Tweedie. Adaptation for the xia, ext2 filesystemand the picture option are done by Alexey Vovenko and Ulrich Habel. Much of the initial version was developed from thefsckandefsckprograms by Linus Torvalds and Remy Card.

Send bug reports, fixes, improvements, comments and fan-mail tosctAATTdcs.ed.ac.uk.

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