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@dircategory Miscellaneous @direntry * e2compr:: User manual for ext2 compression. * e2compress: (e2compr)e2compress. Ext2 compression in user space. * e2decompress: (e2compr)e2compress. Ext2 decompression in user space. * e2bitmap: (e2compr)e2bitmap. Display cluster bitmap. * e2ratio: (e2compr)e2ratio. Ext2 compression statistics.

User's Manual for e2compr-0.3.5

(Comprises former README, FAQ and manual pages.)

Peter Moulder

Incorporating former documentation by Antoine de Maricourt

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the sections entitled "Copying" and "GNU General Public License" are included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Free Software Foundation.


I'd encourage people to read the rest of the manual too, but this page should keep you out of the worst trouble.

Things not to compress
Don't try to compress swap files, kernel images to be loaded with LILO, or files on which you mount a loop device (with losetup). All of these subsystems (swap, loop driver, LILO) access the disk blocks straight from the device rather than going through the filesystem. Other bootloaders, such as grub, are probably the same, though I haven't checked.
Programs to avoid
Don't use a defragmenter or e2dump. See section E2compr interactions with other packages.
Quick notes on lsattr
The `c' flag doesn't indicate whether the file is compressed, it just constitutes a request. If you do `chattr -c file' because you need file to be uncompressed, then you should check it by doing `lsattr file' and checking that no cluster size is displayed for that file. See section What the `c' flag means, for how to correct this. (The usual reason is that the disk is full: clear some space, then `touch file'.)
What's the CONFIG_EXT2_IND_BITMAP option?
Please read the help text available for this option when configuring the kernel, if you wish to enable it. The easiest thing is to keep it disabled. For background information, see section Cluster bitmap, section How does e2compr interact with e2fsck?, and section Can I still use a defragmenter?.
How do I install e2compr?
See the `INSTALL' file that comes with the main e2compr distribution. Main things to look out for are to check for any `.rej' files from patch, and don't enable the CONFIG_EXT2_IND_BITMAP option unless you've installed the modified version of e2fsck.
This manual contains lots more useful information. If you have any trouble, or are wondering how to do something, then this manual is a good place to start.

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