cpio to ext4 seems much slower than to ext2, ext3 or xfs

[Richard W.M. Jones]

On Wed, Nov 11, 2009 at 01:24:20PM -0600, Eric Sandeen wrote:
> Anybody got actual numbers?  I don't disagree that mkfs.ext4 is slow in  
> the default config, but I don't think it should be slower than mkfs.ext3  
> for the same sized disks.

Easy with guestfish:

  $ guestfish --version
  guestfish 1.0.78
  $ for fs in ext2 ext3 ext4 xfs jfs ; do guestfish sparse /tmp/test.img 10G : run : echo $fs : sfdiskM /dev/sda , : time mkfs $fs /dev/sda1 ; done
  ext2
  elapsed time: 5.21 seconds
  ext3
  elapsed time: 7.87 seconds
  ext4
  elapsed time: 6.10 seconds
  xfs
  elapsed time: 0.45 seconds
  jfs
  elapsed time: 0.78 seconds

Note that because this is using a sparsely allocated disk each write
to the virtual disk is very slow.  Change 'sparse' to 'alloc' to test
this with a non-sparse file-backed disk.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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