Alex Zarochentsev wrote: >On Mon, Apr 11, 2005 at 04:30:53PM +0200, Stefan Andersson wrote: > > >>Hi, >> >>I have a disk array wich I used reiserfs(v3) on, and got 932G. >>Now I started to test reiser4 on it and get less space, 886G. >> >>Is it suppose to be like this or is there something wrong? >> >> > >reiser4 reserves 5% of disk space. > >That is so because of delayed block allocation impelented in reiser4. Actual >block allocation is done near the transaction commit, it means the allocation >has to be reliable -- we can't return ENOSPC because the write(2) call when we >could return an error was already completed successfully. > >The reserved space makes the allocation reliable because it covers possible >insertions (and growing of the internal reiser4 tree) of new extent items >insertions on a highly fragmented fs. > > It also improves performance to ensure that at least 5% is free.
> > >>I'am using linux 2.6.11.4 and default settings for mkfs.reiser4 and >>mkfs.reiserfs, >>and reiser4 patch from 2.6.11-mm3. >> >>//Stetan >> >> >> > > >
