Messages in this thread |  | | From | (H. Peter Anvin) | Subject | Re: strange df output? | Date | Mon, 3 Jun 1996 08:31:20 -0700 (PDT) |
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> > > > : Part of the function of the reserved space is to make > > : sure there is enough free space to let the block placement algorithms > > : work efficiently. > > > > Put another way, these numbers are based on how well a hash table > > performs when the alpha of the table (its load) gets high. Most of > > these systems use a hash table to know what it can allocate. > > I believe the BSD 10% is actually a lot simpller to explain, the > (original) algorithm trys to do various optimizationes, one is to > find a contiguous space to put the file in and another is to do so > all in one track. The chances of finding such a place in the file > system (for files of more than a few blocks) drops quite fast as the > disk nears 100% full. So the OS wastes time first to discover that > there is no suitable place to write the file, and secondly having to > fragment the file on disk. An easy way to avoid too much > fragmentation is to simple leave 10% of the disk free. >
You know, guys, we have just explained the same thing three times... it's the same thing.
-hpa
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