linux-ext4 - Large volume ll_ver_fs results (w/ short read/write patch).

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Date:	Mon, 17 Aug 2009 10:55:12 -0400
From:	Nick Dokos <nicholas.dokos@...com>
To:	linux-ext4@...r.kernel.org
Cc:	nicholas.dokos@...com
Subject: Large volume ll_ver_fs results (w/ short read/write patch).

Here are some results of running ll_ver_fs on an ext4 fs created on a
96TB volume. The test was run in full mode: it created 725 directories
each with 32 4GB files and then read everything back with
verification.In summary,

  mkfs: about 30mins
  ll_ver_fs: about 100 hours
  fsck: about 40mins

(a more detailed log is attached).

There were two disk errors encountered that resulted in short reads, but
the patched ll_ver_fs continued on (patch attached). So two chunks (1MB
each) were not completely verified (only the part that was read
successfully was), but the rest of the fs checked out OK. Luckily, the
fsck did not find any errors: both disk errors were in file data.
We have replaced the disks but are not planning to repeat the test: it's
not clear that it would tells us anything more at this point.

Thanks,
Nick

View attachment "results.log" of type "text/plain" (3442 bytes)

View attachment "llverfs.patch" of type "text/plain" (6168 bytes)