Re: Plans to evaluate the reliability and integrity of ext4 against power failures.

[Michael Rubin <mrubin@google.com>]

On Tue, Jun 30, 2009 at 5:58 PM, Eric Sandeen<sandeen@redhat.com> wrote:
> Shaozhi Ye wrote:
> I'll be very interested to see the results.  One thing you will need to
> look out for (people who know me knew I would say this ;) is volatile
> write caches on the storage, and filesystem barrier implementation.

I am interested int he numbers too. As to the other dimensions, we
plan on investigating this as much as we can given our environment.

> To characterize the test, you'll want to be explicit about your storage.
>  Are they local disks?  A Raid controller?  If the disks are external to
> the server, is power lost to the disks?  Do they have write caching
> enabled?  If so do write barriers from the filesystem pass through to
> the storage?  This will all be highly relevant to how a power loss will
> affect the filesystem.


Yup. We plan on detailing these qualities and comparing some of them
in the write up when yeshao's work is done.

> I'm also curious about whether the tool itself will be available under
> an open source license?  Other filesystems would benefit from this
> testing as well.

The end goal is to have a test suite for power loss that we can share
with the community. Realize we may send out numbers before sending out
the tests.

mrubin
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