[olug] Unix Tip: WHY MV IS SLOW

[Unix Guru Universe]

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			         UNIX HOT TIP

			Unix Tip 1999 - June 22, 2003

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WHY MV IS SLOW

mv command across filesystems
is slower on large files

WHY?

mv would be slow if you are 
moving files across filesystem.

The inode number changes only 
when a file is moved across 
file system. 

A new inode number means a new 
file is physically created on 
disk.

It remains unchanged, if it 
is within the same filesystem.
One can verify by using 
ls -il command on that file.

mv uses rename() system call. 
if it fails, it uses copy routine
(basicailly reads from a file and 
writes in another file).

mv command across filesystem is 
more of a copy then mv.


This tip generously supported by: dkotian1 at rediffmail.com


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