On Sunday, June 30, 2013 01:53:48 PM Garry T. Williams wrote:
> I suspect this is, at least in part, related to severe fragmentation
> in /home.
I don't think so. The problem I have described occur only before anybody logs
in to the system and /home being a separate partition, it is not the problem
in this case.
w
>
> There are large files in these directories that are updated frequently
> by various components of KDE and the Chrome browser. (Firefox has its
> own databases that are frequently updated, too.)
>
> ~/.local/share/akonadi
Thats 3.9MB in my case since I point the akonadi db to a systemwide postgresql
instance. of course, it will just shift defragmentation there.
> ~/.kde/share/apps/nepomuk/repository/main/data/virtuosobackend
damn!
# filefrag soprano-virtuoso.db
soprano-virtuoso.db: 10518 extents found
# btrfs fi defrag soprano-virtuoso.db
# filefrag soprano-virtuoso.db
soprano-virtuoso.db: 957 extents found
How much is an extend anyways? is it a page or 256M?
> ~/.cache/chromium/Default/Cache
> ~/.cache/chromium/Default/Media\ Cache
I don't use chromium. but I get the idea.
But in general, how to find out most fragmented files and folders? mouting
with autodefrag is a serious degradation..
> I improved performance dramatically (orders of magnitude) by copying
> the database files into an empty file that was modified with:
>
> chattr -C
>
> and renaming to make the files no COW. (Note that this is the only
> way to change an existing file to no COW.) I also set the same
> attribute on the owning directories so that all new files inherit the
> no COW attribute.
>
> I suspect there are other files that fragment badly since I see
> periods of high disk activity coming back slowly over a few weeks of
> use after making the modifications above. I intend to track them down
> and do the same.
hmm.. a trick to find most badly fragmented files/directories and defragment
them should do too I think.
--
Regards
Shridhar
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