On 08/31/2009 04:56 PM, Andreas Dilger wrote:
On Aug 31, 2009 13:02 -0400, Ric Wheeler wrote:
One more note - this file system was filled using fs_mark, but without
doing any fsync() calls.
umount:
Aug 31 10:19:27 megadeth kernel: EXT4-fs: mballoc: 2580708130 blocks
516141626 reqs (511081408 success)
Aug 31 10:19:27 megadeth kernel: EXT4-fs: mballoc: 5060218 extents
scanned, 0 goal hits, 5060218 2^N hits, 0 breaks, 0 lost
Aug 31 10:19:27 megadeth kernel: EXT4-fs: mballoc: 85164 generated and
it took 471527376
Aug 31 10:19:27 megadeth kernel: EXT4-fs: mballoc: 2590831616
preallocated, 10120312 discarded
Mount after fsck:
Aug 31 12:27:12 megadeth kernel: EXT4-fs (dm-75):
ext4_check_descriptors: Checksum for group 487 failed (59799!=46827)
Aug 31 12:27:12 megadeth kernel: EXT4-fs (dm-75): group descriptors
corrupted!
The MBALLOC messages are a bit worrying - what exactly gets discarded
during an unmount?
The in-memory preallocation areas are discarded. This is reporting
that of the 2590M preallocation areas it reserved, only 10M of them
were discarded during the lifetime of the filesystem.
Of the other stats:
- 471 seconds were spent in total generating the 85k buddy bitmaps
(this is done incrementally at runtime)
- 516M calls to mballoc to find a chunk of blocks, 511M calls were able
to find the requested chunk (not surprising given it is a new filesystem,
probably the 5M calls that failed were when the fs was nearly full)
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
This file system was never more than 7% full - the 511M calls were for each of
the 20KB files more or less I guess.
ric
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