On Mon, Nov 9, 2015 at 3:46 PM, Thomas Leonard <[email protected]> wrote:
> Hi Rupert, > > The main thing is to implement Irmin's AO signature: > > > https://github.com/mirage/irmin/blob/4ccccb5d3117e4cc1ecff4a83cc508da59006423/lib/irmin.mli#L360 > > i.e. given a block of data, write it to disk and return its hash. > Given a hash, return the file data. > > You could write the data sequentially to the disk and keep an index of > where everything has been stored. I guess a first version of this could keep the whole index cached in memory for convenience and write updates to a log, flushing a copy to disk every now and again using double-buffering for example. See mirage-block-volume[1]'s use of shared-block-ring[2] for an example of this. For bigger amounts of data we'd probably want to keep the index on disk too -- perhaps we should have some kind of on-disk b-tree library? I was wondering about the format used by Linux's dm-thin driver[3] Cheers, Dave [1] https://github.com/mirage/mirage-block-volume/blob/2ffe5a1b7fd8db83fec5c3c44bab503b85d52390/lib/vg.ml#L416 [2] https://github.com/mirage/shared-block-ring [3] https://github.com/jthornber/thin-provisioning-tools Or, you could perhaps use the file's > hash to decide where to store it. There's also irmin-chunk > (https://github.com/mirage/irmin-chunk) which says it might help with > raw device backends, although I'm not sure what the idea is there. > > > On 7 November 2015 at 18:11, Rupert Horlick <[email protected]> wrote: > > Hi all, > > > > I’m investigating using Irmin on top of a Mirage BLOCK implementation. > I’ve been reading through the source, but I was wondering if anyone could > point me to the files that will be of most use for this? > > > > Thanks, > > > > Rupert > > _______________________________________________ > > MirageOS-devel mailing list > > [email protected] > > http://lists.xenproject.org/cgi-bin/mailman/listinfo/mirageos-devel > > > > -- > Dr Thomas Leonard http://roscidus.com/blog/ > GPG: DA98 25AE CAD0 8975 7CDA BD8E 0713 3F96 CA74 D8BA > > _______________________________________________ > MirageOS-devel mailing list > [email protected] > http://lists.xenproject.org/cgi-bin/mailman/listinfo/mirageos-devel > -- Dave Scott
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