Re: ext2 compression: How about using the Netware principle?

[Anders K. Pedersen]

Pavel Machek wrote:
> > - A file is saved to disk
> > - If the file isn't touched (read or written to) within <n> days
> > (default 14), the file is compressed.
> > - If the file isn't compressed more than <n> percent (default 20), the
> > file is flagged "can't compress".
> > - All file compression is done on low traffic times (default between
> > 00:00 and 06:00 hours)
> > - The first time a file is read or written to within the <n> days
> > interval mentioned above, the file is addressed using realtime
> > compression. The second time, the file is decompressed and commited to
> > disk (uncompressed).

Also, if less than <n> percent of the volume is free, files will not be
decompressed, and compressed files can only be addressed through
realtime decompression.

> Oops, that means that merely reading a file followed by powerfail can
> lead to you loosing the file. Oops.

That is of course not the case. When a file is decompressed (or
compressed) a new file is created, and once the (de)compression is
completed, a delete and rename will be performed, and this is, if I
remember correctly, transaction based, so the file will not be lost in
case a powerfail should occur.

Regards,
Anders K. Pedersen