Re: out-of-band dedup status?

[Adam Borowski <kilobyte@angband.pl>]

On Thu, Dec 08, 2016 at 07:54:39PM -0700, Chris Murphy wrote:
> On Thu, Dec 8, 2016 at 7:26 PM, Darrick J. Wong <darrick.wong@oracle.com> wrote:
> > Ew, it's deduping these two 1.4GB files 128K at a time, which results in
> > 12000 ioctl calls.  Each of those 12000 calls has to lock the two
> > inodes, read the file contents, remap the blocks, etc.  instead of
> > finding the maximal identical range and making a single call for the
> > whole range.
> >
> > That's probably why it's taking forever to dedupe.
> 
> Yes but it looks like it's also heavily fragmenting the files as a
> result as well.

Thus I think it's better to do whole-file dedupe only, other than in some
special cases (like VM images).  Much simpler, faster and doesn't cause
fragmentation.

-- 
u-boot problems can be solved with the help of your old SCSI manuals, the
parts that deal with goat termination.  You need a black-handled knife, and
an appropriate set of candles (number and color matters).  Or was it a
silver-handled knife?  Crap, need to look that up.