[Caml-list] [ANN] Plasma MapReduce, PlasmaFS, version 0.2
Gerd Stolpmann
I've just released Plasma-0.2. Plasma consists of two parts (for now),
namely Plasma MapReduce, a map/reduce compute framework, and PlasmaFS,
the underlying distributed filesystem.
Major changes in version 0.2 :
* Enhanced filesystem operations, with enhanced locking
* Full support for symbolic links
* Extended filesystem API, both in the ocaml module and the
command-line utility
* One can now mount filesystems read-write via NFS
* Map/reduce processes files in larger chunks than before
* Streaming (as in Hadoop)
* Support for per-task logging
Of course, there are also numerous bug fixes and performance
improvements.
Plasma MapReduce is a distributed implementation of the map/reduce
algorithm scheme. In a sentence, map/reduce performs a parallel List.map
on an input file, sorts and splits the output by some criterion into
partitions, and runs a List.fold_left on each partition. Only that it
does not do that sequentially, but in a distributed way, and chunk by
chunk. Because of this Plasma MapReduce can process very large files,
and if run on enough computers, this also will work in reasonable time.
Of course, map and reduce are Ocaml functions here.
This all works on top of a distributed filesystem, PlasmaFS. This is a
user-space filesystem that is primarily accessed over RPC (but it is
also mountable as NFS volume). Actually, most of the effort went here.
PlasmaFS focuses on reliability and speed for big blocksizes. To get
this, it implements ACID transactions, replicates data and metadata with
two-phase commit, uses a shared memory data channel if possible, and
monitors itself. Unlike other filesystems for map/reduce, PlasmaFS
implements the complete set of usual file operations, including random
reads and writes. It can also be used as unspecialized global
filesystem.
Both pieces of software are bundled together in one download. The
project page with further links is
http://projects.camlcity.org/projects/plasma.html
This is an early alpha release (0.2). A lot of things work already, and
you can already run distributed map/reduce jobs. However, it is in no
way complete.
Plasma is installable via GODI for Ocaml 3.12.
For discussions on specifics of Plasma there is a separate mailing list:
https://godirepo.camlcity.org/mailman/listinfo/plasma-list
Gerd
--
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Gerd Stolpmann, Bad Nauheimer Str.3, 64289 Darmstadt,Germany
ge...@gerd-stolpmann.de http://www.gerd-stolpmann.de
Phone: +49-6151-153855 Fax: +49-6151-997714
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