[Sheepdog] [PATCH RFC v4] add a new store named 'farm'

[Christoph Hellwig]

On Wed, Dec 28, 2011 at 10:12:40PM +0800, Liu Yuan wrote:
> Let's stay with Farm's working directory for regular data operations, in
> order to gain comparable I/O performance, suitable for general workloads.

I'd love to know what the performance impact is.  Obviously we'd use
more CPU, but most storage workloads are disk-bound, not CPU bound.

> I think LevelDB will match what you desire, they do tricks optionally
> when they 'put' those objects into persistent storage. I am having it in
> mind to adopt LevelDB as Sheepdog's backend store later, (not a promise,
> though I guess it's just several hundred lines to implement a LevelDB
> driver). ;)

I didn't know leveldb, let me take a look what it does.

> If we really need this feature inside Farm, I can accept it whoever
> implement this feature in Farm, if Farm could dynamically choose
> callbacks how to read/write regular objects.

I don't really need it.  I've just started to read through farm and try
to understand the concept.  The use the SHA id for everything was my
initial impression of how it worked, which turned out to be false.  I've
just been wondering if it might be a good idea in the end.