mutable store on mirage?

[Christopher Greenhalgh <Chris.Greenhalgh@xxxxxxxxxxxxxxxx>]

is there currently a sensible option for a mutable datastore in mirage? 
i'd like to make an interactive web site/service and need at least the 
equivalent of a persistent mutable key-value store with user-defined keys (e.g. 
to take a minimal example, key = user ID, value = current user profile 
information).

a) I guess i could port baardskeerder - has that been done already?

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?

c) in a previous incarnation of mirage i started to write a mutable (strictly 
append only) key/value over that version of blkif, but ran out of time/energy; 
is this obviously a waste of time/duplication of effort or would it be 
useful/sensible?  

d.1) is there any reason for/against persisting directly against blkif in 
mirage? i,e, with not filesystem abstraction?
d.2) as far as i can see the only up-to-date filesystem in mirage is the crunch 
RO fs; the fat fs is mostly there but need porting to the latest blkif 
interface, and there aren't any others at the moment - is that right?!

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?

cheers
chris
This message and any attachment are intended solely for the addressee and may 
contain confidential information. If you have received this message in error, 
please send it back to me, and immediately delete it.   Please do not use, copy 
or disclose the information contained in this message or in any attachment.  
Any views or opinions expressed by the author of this email do not necessarily 
reflect the views of the University of Nottingham.

This message has been checked for viruses but the contents of an attachment
may still contain software viruses which could damage your computer system, you 
are advised to perform your own checks. Email communications with the 
University of Nottingham may be monitored as permitted by UK legislation.