Re: [Qemu-devel] [RFC PATCH 0/2] GlusterFS support in QEMU - v2

[Vijay Bellur <vbellur@redhat.com>]

On 07/23/2012 02:20 PM, Bharata B Rao wrote:

>
>> 2. It is currently not possible to bypass RPC because the glusterd
>> managed configuration file doesn't support that.
>
> It is possible. Gluster already supports custom extensions
> to volume names and it is possible to use the required volfile by specifying
> this custom volname extension.
>
> For eg, if I have a volume named test, by default the volfile used for
> it will be test-fuse.vol. Currently I can put my own custom volfile into
> the standard location and get glusterd pick that up. I can specify
> test.rpcbypass as volname and glusterd will pick test.rpcbypass.vol.
>
> What is currently not supported is the ability to create test.rpcbypass.vol
> from gluster CLI. I believe that gluster developers are ok with enhancing
> gluster CLI to support generating/regenerating volfiles for a given volume
> with custom translator set.


Yes, this would be the preferred approach. We can tune the volume file 
generation to evolve the desired configuration file.

>
>>
>> I'm not sure if these statements are true?
>>
>> Would you support local volfiles in the future again?  Why force users
>> to run glusterd?
>
> I will let gluster folks on CC to answer this and let us know the benefits
> of always depending on glusterd.
>
> I guess running glusterd would be beneficial when supporting migration. QEMU
> working from a local volume (with volname=test.rpcbypass) can be easily
> restarted on a different node by just changing volname to test. glusterd will
> take care of fetching the right volfile automatically for us.

Yes, running glusterd would be beneficial in migration. Without deriving 
the file from glusterd features like volume tuning, client monitoring 
etc. would not be available to to clients that talk to a gluster volume. 
Additionally, driving configuration generation and management through 
glusterd helps in standardizing and stabilizing gluster configurations.

>

>>
>> Has libgfapi been released yet?
>
> Its part of gluster mainline now.
>
>> Does it have versioning which will
>> allow the QEMU GlusterFS block driver to build against different
>> versions?  I'm just wondering how the pieces will fit together once
>> distros start shipping them.
>
> I request gluster folks on CC to comment about version and shipping
> information.
>

There is no release that contains libgfapi as yet. Once that is done, we 
can probably have the dependency specified in QEMU as well.

Regards,
Vijay