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Thu, 29 Mar 2007

FS userspace emulation tool.


Ok, here are features I will implement:

• a library which will provide synchronous read and write calls, each one will get sector number and amount of bytes (maybe with vectored variants). Each such call will block until data is really written/read, i.e. it will include cost for sequential write/read and seek into the place.
• simple FS implementation, which will take a 'storage' size and divide it into fixed size blocks, which will form a bitmap of used/free elements. Then I will use random models to test that FS - work with several big files, with a lot of small files and so on, no directories so far. That will show what disk usage patterns are common for different loads, main goal to find a solution which will have the smallest amount of disk seeks, which are extremely slow.
• start more complex FS implementation with this set of features as a must

/devel/fs :: Link / Comments (0)

New wine and recent happenings.


'Rose d'Anjou. Henry Le Cuvier' - french dry wine - not tasty, no special spirit, almost water. Will not buy.

Wine which helped to crack 2 of 9 Jenkins hash rounds - 'Sunrise Merlot' by 'Vina Concha y Toro' - Chile red dry wine - extremely tasty thing, will buy it again if there will not be any better variants.

I did not write for my climbing trainig progress so far - I do climb three times per week about 2.5-3 hours each, still train alone, sometimes with weights - mostly compelx boulderings and traverses on the second set of shields (1 meter high) - that make me tired as hell, which is exactly the purpose - every piece of body (even head brain some times, although that happens extremely rarely) need to work I think.
Tried (although I did not want to change anything too much) to change life style (as Grange call it) - stopped after initial steps - call me lazy boom slacker.
Found, that I can do only three things after training - to do nothing, to eat and drink and to do somthing I will not tell you. Everything a lot.
Feel myself extreemly good.

Had a talk with my boss and company CEO - such talks never happen when people want to thank you or rise a salary (it rises once per year with smaller than inflation rate), so I got a bunch of shit on my head. And I needed to lie, which I never (hmm, almost) do - but how can I tell them that the most interesting things I did for the last several years were my own projects, which did not affect (almost) my main work - I said, that although I really do not like what I do, it must be done and so on.
Think about doing for my own again - but there are some problems (as usual)...

/life :: Link / Comments (0)

The 2007 Linux Storage and File Systems Workshop.


LWN article and wiki notes.

Interesting notes:

• extended attributes must have variable lengths to satisfy various usage cases (crypto, ACL)
• fsck is evil, it can be fixed by changing meta-data location to eliminate seeks
• disk encryption should not depend on external subsystems like SELinux
• stackable filesystems work badly when underlying filesystem in the stack is modified directly
• ShadowFS - way to use some kind of write-anywhere-filesystem-layout - when data is being written into the file, old data is not owerwritten, but instead write happens into different area on disk, so system is never in inconsistent state if there were some errors (power failure, shutdown and so on
• a short description of several filesystems (NFS, GFS2, OCFS2, DualFS) and eXplode - bug searching tool, which is known to help finding bugs in every Linux filesystem recently

/devel/fs :: Link / Comments (0)