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SubjectRe: multiply files in one (was GNU/Linux stance by Richard Stallman)
Date
From
: 
: Larry McVoy writes:
: > : What I was getting at
: > : was that if you pack the data together, then read-ahead will yield
: > : more complete files, which translates to less transactions in the end.
: >
: > Read ahead really doesn't solve the problem for two reasons:
: >
: > 1) the allocation policies in almost all file systems is file
: > centric - it's careful to get *a* file contiguous but isn't
: > careful to get multiple files in the same directory all next
: > to each other
:
: 1) is solved in reiserfs.
:
: >
: > 2) even if (1) was solved, the file system needs to know that it
: > bring in more data. If the file it is reading is 1K long,
: > why should it brin in the next 5MB of data?
:
: I don't understand. How does this differ from any other sort of
: read-ahead?

We need read ahead algs on directories where the data being read ahead is
the file data, not the directory data. I.e., I read on file in this
directory, then the next, then the next, then the next, screw it, I'm
reading the whole directory including all of its files.

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