Messages in this thread | | | Date | Wed, 14 Jul 1999 22:16:18 -0700 | From | merblich <> | Subject | Re: Large disk partition over 300GB |
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To shed some light on this.
Normally, a file system will allocate disk blocks based on a time vs space algorithm. By having blocks free in a number of locations, the best location to allocate the disk block due to the growing of fragments or just a new block can be realized. A couple of factors in determining this is interleave, rotation speed, time to seek, etc.
Once the file system's free space decreases to a specified point, the allocation then just allocates blocks due to their availability. My guess, is that 5% is the point where this tradeoff is made.
Mitch ========
Stephen C. Tweedie wrote: > > Hi, > > On Tue, 13 Jul 1999 09:38:30 +0000, Thierry Vignaud > <tvignaud@mandrakesoft.com> said: > > > Miquel van Smoorenburg wrote: > >> The reason that 5% of disk space is reserved is to always have some > >> room left. The ext2 allocation algorithm needs this to prevent > >> fragmentation. > > > I think the main reason is to let the sysadmin to fix the system in case > > of problem and to prevent users from filling all the free space. > > Partly that... > > On Tue, 13 Jul 1999 15:52:31 +0400 (MSD), "Khimenko Victor" > <khim@sch57.msk.ru> said: > > > And you can NOT use this room for conf files editing (unless you are > > root, of course)... No, main reason is to give ext2fs defragmentation > > algorithm space to breathe. > > Most config files _are_ edited by root, but ext2 defragmentation is an > equally good reason. > > Why does one reason have to be wrong? If we have two valid reasons for > doing something, do we have to own up to only one of them? > > When we added this stuff it was primarily for fragmentation, but we were > fully aware of the fact that it would be a failsafe for root at the same > time. They are both good reasons for keeping a reserved portion. > > --Stephen > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.rutgers.edu > Please read the FAQ at http://www.tux.org/lkml/
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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