[Pvfs2-developers] patches: pvfs2-ping, pvfs2-genconfig, test programs

[Phil Carns]

Robert Latham wrote:
> On Thu, Apr 06, 2006 at 02:40:01PM -0600, Bart Taylor wrote:
> 
>>As an example, suppose that you are using a SAN and you want one particular
>>server to have a dedicated LUN for metadata.  In that case you might want to
>>specify something like this:
>>--iospecs host1:3335:/mnt/data-lun,host2:3335:/mnt/data-lun
>>--metaspces host1:3334:/mnt/meta-lun
> 
> 
> It sounds like what you want, more than iospecs and metaspecs, is a
> way to specify separate storage spaces for metadata and data.  
> 
> ==rob

I just ran across this email when looking for a reference to the 
pvfs2-ping patch, but I thought I would add my 2c.

I think for the range of cases that Bart was addressing it isn't 
necessarily as simple as choosing different storage for meta vs. I/O 
(although that would work for this example).  Having more flexibility in 
terms of the exact server specification can be helpful for unusual 
server environments, like:

- multiple servers per node on some machines (to access multiple LUNs on 
systems with LUN size limitations)
- tuning subsets of servers for specific purposes (maybe some have 
different RAM or other hardware footprints)
- temporarily doubling up servers on just one of the machines, so that 
you can take a different one off line for maintenance (mainly useful if 
you have network attached storage that other servers could reach)

We haven't necessarily seen all of these configurations, but it would be 
nice to be able to handle all of those cases with the same command line 
interface.

There may be a cleaner way to represent all of this in general, but this 
patch was also trying not to break existing arguments to genconfig.

-Phil