Re: Reiser4 bitmap & replication handling

["Fred -- Speed Up --" <speedup@free.fr>]

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> well, his words are not quite that strong, and who knows if he is using
> the latest journaling patches but XFS is a very nice filesystem.....
You're speaking from Reiser 3.6 right ? Are these patches included in 2.4.20
or 2.4.21 official kernel sources ?

> Well, Reiser4 has much fewer seeks than other filesystems usually.  The
> current weakness of Reiser4 is CPU consumption, but our team is cutting
> that down at great speed.  It seems like each team member manages to
> reduce it by >10% a week, and there are 3 of them working actively on
> that.  This is fortunate, because it is still very high.....  I have
> this fond hope that performance will be something very nice by
> LinuxTag.....;-)
I really hope so, performance is a big point for the Reiser filesystem ;)
You say the CPU is now the weakness ... but how do you handle with large
file read/write operations : in this case, the HDD performance level should
come first ?
Great part of the Reiser4 team is working on performance tweaking : does
this mean that Reiser has come into the final stage, that it has now proven
stable so that performance improvement is the only thing to achieve before
RC and/or release ? Did you published a release plan, with public beta and
RC or do you want to test Reiser4 internally ? I know Reiser4 is available
as a 2.5 kernel patch, but do you plan to build a dedicated structure to
report bugs found in early Reiser4 versions ?

> what do you mean, replicate the tree?
I mean, for security pruposes, does Reiser4 maintain copies of the storage
tree or does it simply trust its marvelous journalising system ?

> bitmaps.;-) we have some nice little tweaks, like we count the number of
> used bits in every bitmap block so that we don't have to scan full
> blocks, and we hash around if we scan too much, but I have to say that
> bitmaps are nice and simple and work without a lot of code.
I wad afraid Reiser4 didn't had the best bitmap-handling system over there,
now I'm reassured thank you :-D

> >Are you implementing some special features for very large disks,
> how are they different
Maybe some really big files handling performance improvements, to near XFS
performance in this domain. I'm not really concerned, but some specific
systems may need such features only offered by XFS. Do you plan to release
different versions of the filesystem's plugins to adapt to different systems
ans situations ?

> Reiser4 inconsistently performs very very fast.  We have no doubt that
> we can make that consistent but it is a lot of measuring and tweaking
> and measuring and tweaking.....
Sorry but ... what do you mean by "unconsistently" ? Does this mean you only
consider avarage performance, ignoring worse cases ?
Again, do you plan to ask some external testers to tweak Reiser4 ?

> >I didn't remember, when do you plan to release Reiser4 ?
> >
> LinuxTag, July 11, if lucky, we will start our beta.
Outstanding ... I hope you'll be sucessfull, but I'm not really scary about
that ;)
Another question, do you want to release Reiser4 so that it will be
presented on LinuxTag because :
1- The developement team is mainly composed of german people
2- Suse will have a very big area on the show
3- The release date just accorded to the LinuxTag opening
4- All of you especially like LinuxTag :-D


Thank you Hans,

Fred