Messages in this thread | | | From | (Linus Torvalds) | Subject | Re: [BK][PATCH] Reiser4, will double Linux FS performance, pleaseapply | Date | Fri, 1 Nov 2002 04:36:12 +0000 (UTC) |
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In article <3DC1D9D0.684326AC@digeo.com>, Andrew Morton <akpm@digeo.com> wrote: > >But it should be done based on "feature equivalency". By default, >ext3 uses ordered data writes. Data is written to disk before >the metadata to which that data refers is committed to journal.
Andrew, that's not necessarily a _good_ feature.
Journaling is _not_ a great idea. There are other approaches to handling atomicity than journaling, like phase trees, that give equivalent atomicity guarantees without having to write out extra stuff, or even impose a very strict ordering between data and meta-data.
I didn't read the reiser papers yet, but from Hans' description it sounds like reiser4 gives all the guarantees ext3 does with ordered writes, _and_ they get good performance.
(In fact, from the description it sounds like it gives _more_ guarantees than even ext3 with ordered writes, in that it gives transactional behaviour for arbitrary writes. Maybe I should read the paper).
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