Why is restore so slow?

[Chris Torek]

In article <480 at appserv.Eng.Sun.COM> lm at Eng.Sun.COM writes:
>I believe that a key component to the slowness of restore is the
>synchronous nature of directory operations in the Unix file system.
>For example, a create, something that occurs quite often in restore
>:-), is synchronous.  It has to be, those are the semantics of a Unix
>file system (can you say lock files?).

(Funny to hear someone from Sun arguing for Unix FS semantics :-) )

Seriously, `synchronous' is more restrictive than necessary.  Directory
operations must be ordered.  They need not be complete by the time the
call returns.  If they are properly ordered, the inode will exist before
the directory entry, and the directory entry will exist before the first
file block appears, so that fsync() will guarantee that the file exists
and is in permanent storage.
-- 
In-Real-Life: Chris Torek, Lawrence Berkeley Lab EE div (+1 415 486 5427)
Berkeley, CA		Domain:	torek at ee.lbl.gov