[gpfsug-discuss] OpenStack Manila Driver

Jonathan Buzzard jonathan at buzzard.me.uk
Mon Jun 15 15:16:44 BST 2015


On Mon, 2015-06-15 at 08:35 +0000, Luke Raimbach wrote:
> Dear All,
> 
> We are looking forward to using the manila driver for
> auto-provisioning of file shares using GPFS. However, I have some
> concerns...
>
> 
> Manila  presumably gives tenant users access to file system commands
> like mmlinkfileset and mmunlinkfileset. Given that mmunlinkfileset
> quiesces the file system, there is potentially an impact from one
> tenant on another - i.e. someone unlinking and deleting a lot of
> filesets during a tenancy cleanup might cause a cluster pause long
> enough to trigger other failure events or even start evicting nodes.
> You can see why this would be bad in a cloud environment.

Er as far as I can see in the documentation no you don't. My personal
experience is mmunlinkfileset has a habit of locking the file system up;
aka don't do while the file system is busy. On the other hand
mmlinkfileset you can do with gay abandonment. Might have changed in
more recent version of GPFS. 

On the other hand you do get access to creating/deleting snapshots which
on the deleting side has in the past for me personally has caused file
system lockups. Similarly creating a snapshot no problem.

The difference between the two is things that require quiescence to take
away from the file system can cause bad things happen. Quiescence to add
things to the file system rarely if ever cause problems.


JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Fife, United Kingdom.





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