Lustre discuss - Sep 2012 - What is the state of sub-tree locking?

Hi,

We are trying to figure out whether it is possible to build a client-side
cache system over Lustre in order to speed up the perforamance of our
applications. In this system, we need to protect cached files and
directories from being changed by other clients. The per-file group lock
may not be enough since we need to protect the whole namespace including
metadatas. I think sub-tree locking may help a lot, though it is not
designed for this purpose. Any way, may I ask what time can we expect
sub-tree lock to be released? Is there any prototypical source codes?

Thanks a lot.

Li Xi
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On 2012-09-09, at 11:34 PM, ?? wrote:
> We are trying to figure out whether it is possible to build a client-side
cache system over Lustre in order to speed up the perforamance of our
applications. In this system, we need to protect cached files and directories
from being changed by other clients. The per-file group lock may not be enough
since we need to protect the whole namespace including metadatas. I think
sub-tree locking may help a lot, though it is not designed for this purpose. Any
way, may I ask what time can we expect sub-tree lock to be released? Is there
any prototypical source codes?
There was no development work done for sub-tree locking for Lustre.  This was
only a proposed feature, but it never started development.

Cheers, Andreas
--
Andreas Dilger                       Whamcloud, Inc.
Principal Lustre Engineer            http://www.whamcloud.com/