On Wed, 2002-11-13 at 19:39, LA Walsh wrote:
>
> My system looks like: (files/dirs).
> /:
> xfs_db: actual 152457, ideal 152451, fragmentation factor 0.00%
> xfs_db: actual 4090, ideal 3459, fragmentation factor 15.43%
> /boot:
> xfs_db: actual 58, ideal 58, fragmentation factor 0.00%
> xfs_db: actual 2, ideal 2, fragmentation factor 0.00%
> /tmp:
> xfs_db: actual 6, ideal 6, fragmentation factor 0.00%
> xfs_db: actual 0, ideal 0, fragmentation factor 0.00%
> /var:
> xfs_db: actual 15924, ideal 14822, fragmentation factor 6.92%
> xfs_db: actual 276, ideal 206, fragmentation factor 25.36%
> /home:
> xfs_db: actual 104276, ideal 100041, fragmentation factor 4.06%
> xfs_db: actual 4586, ideal 4474, fragmentation factor 2.44%
> /backups:
> xfs_db: actual 1952, ideal 660, fragmentation factor 66.19%
> xfs_db: actual 16, ideal 11, fragmentation factor 31.25%
> ----
> This is with no xfs_fsr (since it doesn't exist on my system)
> with
> fs's about 9 months old, maybe?
>
> Looks like I could use a good xfs_fsr. Am running SuSE8.1 and
> doesn't appear they included it.
I don't think you do, if you look at the actual numbers, only one
filesystem is really fragmented, the /backups one, and it does
not have many files. Also you cannot defragment directories.
We package fsr with dump/restore which is a separate rpm, so
see if you have on of those.
>
> > Then freesp lists the sizes of freespace:
> >
> > from to extents blocks pct
> > 1 1 461 461 0.11
> > 2 3 335 776 0.18
> > 4 7 215 1135 0.26
> > 8 15 231 2611 0.60
> > 16 31 149 3249 0.75
> > 32 63 155 6930 1.60
> > 64 127 153 13900 3.21
> > 128 255 139 25120 5.80
> > 256 511 80 29159 6.74
> > 512 1023 40 26903 6.21
> > 1024 2047 12 17903 4.14
> > 2048 4095 6 18091 4.18
> > 4096 8191 1 4628 1.07
> > 8192 16383 1 14674 3.39
> > 32768 65535 5 267378 61.76
> ---
> So, ideally, would all of the extent ranges have at most 1 extent --
> except
> for the 32768-65535 range which would have some number of extents
> equivalent to something close to free blocks/64K?
No, these are just arbitary buckets for reporting purposes, you
can make it output it differently I think.
> As for me doing 'timings and testings'...I can add that to my
> 'list'...of
> things it would 'be good to do'...:-). Seriously though -- perhaps I am
> naïve, but someone must have thought there was some benefit to be gained
> by
> having a defrag utility for xfs. As mentioned -- it's not that common
> on
> *nixes. So I'm wondering what/who (maybe unknown after many years)
> prompted
> the creation of such a utility. Someone must have thought either
> thought
> it was needed or that it would make a difference. I realize, though,
> that
> doesn't mean there was any hard evidence and could have been added on a
> whim :-).
>
> linda
>
It was written for some media customers who were managing to create
pathologically fragmented files which could not then be streamed
of the disk at a decent speed. If you know how to you can make
xfs fragment files really badly.
Steve
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