Re: Do we need dump for ext4?

[Eric Sandeen <sandeen@redhat.com>]

Andreas Dilger wrote:
> On Aug 29, 2008  07:36 -0500, Eric Sandeen wrote:
>> at Ric & hch's  request here is tar on the other fs's as well, re-sorted
>>  by level 0 dump time.  I put acp into the mix as well.
>>
>> Oh, and this time I remembered to set the elevator to something sane
>> (noop) for this storage, oops (was cfq last time)
>>
>> Also, this time the dup/tar/acp was written to /dev/null rather than
>> another filesystem.  Interesting how routing to /dev/null alone changed
>> the ranking quite a bit.
> 
> Note that tar has a (questionable) optimization when writing to /dev/null.
> It will NOT open the file or read the data, and just do the filename
> traversal to generate the file list and total file size.  It does this by
> comparing the output file to "/dev/null":

Ah, crud.

-Eric