[openstack-dev] [Nova] Default ephemeral filesystem

Sean Dague sean at dague.net
Thu Dec 19 20:30:03 UTC 2013


On 12/19/2013 03:21 PM, Robert Collins wrote:
> The default ephemeral filesystem in Nova is ext3 (for Linux). However
> ext3 is IMNSHO a pretty poor choice given ext4's existence. I can
> totally accept that other fs's like xfs might be contentious - but is
> there any reason not to make ext4 the default?
> 
> I'm not aware of any distro that doesn't have ext4 support - even RHEL
> defaults to ext4 in RHEL5.
> 
> The reason I'm raising this is that making a 1TB ext3 ephemeral volume
> does (way) over 5GB of writes due to zeroing all the inode tables, but
> an ext4 one does less than 1% of the IO - 14m vs 7seconds in my brief
> testing. (We were investigating why baremetal deploys were slow :)).
> 
> -Rob

Seems like a fine change to me. I assume that's all just historical
artifact.

	-Sean

-- 
Sean Dague
Samsung Research America
sean at dague.net / sean.dague at samsung.com
http://dague.net

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