fsck times/memory sizes/etc

[Pawel Jakub Dawidek]

On Wed, Feb 14, 2007 at 08:51:36AM -0600, Eric Anderson wrote:
> I just did some quick playing around, doing newfs and fsck's on fresh file systems.  I did one set on a 1Gb malloc'ed md, and another on a 65GB real disk device.  The disk 
> was only being used for this test, nothing else.
> 
> I don't claim these numbers are perfect, but I did run each test 3-4 times to make sure they were consistent.
> 
> I found it interesting that the fsck times didn't reduce once all the files/directories were deleted.

This may be because of UFS2 has lazy inodes allocator - it doesn't
initialize all inode blocks at newfs time, so fsck verifies only
allocated inode blocks, thus runs faster on new file system.
When you fill your file system, inode blocks are allocated, but are not
reclaimed when you delete file/directories.
You may try the same tests with UFS1, which allocates all inode blocks
at newfs time.

-- 
Pawel Jakub Dawidek                       http://www.wheel.pl
pjd at FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!
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