At 07/21/2016 04:13 PM, John Ettedgui wrote:
On Thu, Jul 21, 2016 at 1:10 AM Qu Wenruo <quwen...@cn.fujitsu.com
<mailto:quwen...@cn.fujitsu.com>> wrote:
Thanks for the info, pretty helpful.
After a simple analysis, the defrag did do a pretty good job.
-----------------------------------------------------------------------
| Avg Extent size | Median Extent size | Data Extents |
-----------------------------------------------------------------------
Predefrag | 2.6M | 512K | 1043589 |
Postdefrag | 7.4M | 80K | 359823 |
Defrag reduced the number of extents to 34%!
Quite awesome.
While I still see quite a lot small extents (In fact, small extents are
more after defrag), so I assume there can be more improvement.
But considering the mount time is only affected by number of extents
(data and meta, but amount of meta is not affect by defrag), so the
improvement is already quite obvious now.
Much more obvious than my expectation.
Thanks,
Qu
I'm glad to be of help.
Is there anything else you'd like me to try?
I don't have any non-defragmented partitions anymore, but you already
got that information so that should be ok.
Thank you,
John
No more.
The dump is already good enough for me to dig for some time.
We don't usually get such large extent tree dump from a real world use case.
It would help us in several ways, from determine how fragmented a block
group is to determine if a defrag will help.
Thanks,
Qu
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