[Lustre-devel] imperative recovery

[Nicholas Henke <nic@cray.com>]

Robert Read wrote:
> 
> On Jan 9, 2009, at 07:27 , Nicholas Henke wrote:

>>
>> I do think this will miss a significant case: combo MGS+MDS. A 
>> majority of our
>> customers are deploying with this configuration. Perhaps exposing this 
>> mechanism
>> on the clients via a /proc file would be enough - that way a failover 
>> framework
>> could manually trigger the timeout and/or nid switching.
> 
> Yes, exactly what I was thinking. Exposing this feature via proc (or 
> lctl) on the clients is the first step. It's has minimal impact, 
> requires no changes to the server, and should integrate well with 
> existing failover frameworks.  We also need to get the server to end 
> recovery sooner (without waiting for all the stale exports), but VBR 
> should help with that.
> 
> robert

FWIW: we'd prefer /proc. We don't ship lctl on our computes for memory 
(initramfs) usage reasons. Being in /proc makes it easy for someone to use the 
functionality from another kernel module as well; we can just call the .read or 
.write functions directly.

Nic