Re: mutable store on mirage?

[Thomas Gazagnaire <thomas@xxxxxxxxxxxxxx>]

Hi,

> b) 've had a look at irminsule, but
> b.1) at the moment i don't actually get how you would use it in this kind of 
> scenario, e.g. does my user defined key (e.g. user login) map to a tag and a 
> value (e.g. their current profile information) to a value? or does the whole 
> current key/value state (i.e. user ID/value for all current users) map to a 
> single value and the 'current state' to a single tag? or something else??
> b.2) is there currently a mirage (non-unix) backend for it?

I'm working to make irminsule more usable at the moment, and I plan to make a 
first release for the end of the month. But yes, you are right, for now that's 
just a proof of concept, so I won't use it in production (yet).

> https://github.com/mirage/mirage-www/pull/38
>  
> e) the mirage-unix OS has a skeleton blkif (over file) implementation but 
> this is currently unimplemented; is it worth implementing and using this for 
> posix or do we expect to use something like dave's ocaml xen-block-driver and 
> xen-disk to emulate block devices from files instead even on posix targets?
> 
> I'd like to see unix blkif implemented (without using the xen 
> implementation). I've got some patches lying around which open files with 
> O_DIRECT and perform unbuffered sector-aligned I/O. I was thinking of making 
> a 'unix-block-driver' with this code in it, mirroring the xen implementation. 
> It's mostly a thin veneer over Lwt_bytes, replacing Bigarray.t with 
> Cstruct.t. In future I was thinking the mirage-platform repo could become the 
> minimal 'boot' code plus module types for Blkif, Netif etc; and all the 
> concrete implementations could be spun out into other repos.
> 
> What do people think?

I think that will be *very* useful.

Then, using this to build a simple (but efficient) append-only k/v store 
(string -> Cstruct.t) with an interface which looks similar on linux and xen 
would be great!

Thomas