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From: "Theodore Ts'o" <tytso@mit.edu>
To: Dmitry Monakhov <dmonakhov@openvz.org>
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Subject: Re: [GIT PULL] ext4 updates for 3.9
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On Thu, Feb 28, 2013 at 12:58:55AM +0400, Dmitry Monakhov wrote:
> Indeed. That's why i give-up rotated disks and run xfstest only on SSD
> or brd module 

Note that some problems only show up on slower devices (because then
the race window is wider), and sometimes they only show up on fast
devices.  This is why I've been doing runs on both HDD's and on tmpfs
kvm disk image files.

> Later we can simply run xfstest/fio/fsx on this image.
> I'll prepare new xfstest based on that idea. But the only disadvantage
> is that loop dev has bottleneck, all requests will be serialized on i_mutex.

If the image file is used as a disk file for KVM, that should avoid
the serialization bottleneck of using the loop device.

Regards,

						- Ted