[infinispan-dev] HDFS FileStore

[Radim Vansa]

On 05/13/2016 04:07 PM, Cristian Malinescu wrote:
> Hi Gustavo - thanks for the guidance!
> Have some questions -
> 1. ISPN-2940 <https://issues.jboss.org/browse/ISPN-2940> - says the 
> idea isn't new and it didn't got a 'Go' at that moment. If we proceed 
> with this work, does it mean a reopening of the item?
> 2. Couldn't see any design docs for both SingleFile and SoftIndexFile 
> store(s) subsystems - fairly, couldn't find design docs for any of the 
> pluggable
>      cache store modules. I want to start from one of them to keep 
> consistency and compatibility in style for easiness of adoption.

The design doc was not needed if the author was not in the need of 
discussing the design prior to implementation. SingleFileStore design is 
rather simple:
* in-memory key-position_in_file map
* place data to any unoccupied spot in the file or prolong the file
* keep list of unoccupied spots in size-based tree

and SoftIndexFileStore has the design described in the javadoc for the 
main class (SoftIndexFileStore.java). If you have any questions wrt 
SIFS, I am the one to answer them.

Radim

> 3. Was the HDFS store idea abandoned because just using HBase would 
> pretty much offer the same with the advantage of offloading on HBase 
> the need
>     for compaction due to the append-only nature of HDFS?
>
> Cheers
> Cris
>
> On Thu, May 12, 2016 at 10:52 AM, Gustavo Fernandes 
> <gustavo at infinispan.org <mailto:gustavo at infinispan.org>> wrote:
>
>     Hi Cristian!
>
>     A HDFS cache store [1] looks interesting, and given the
>     append-only nature of HDFS, I'd say probably the SoftIndex is
>     better to look at than the SingleFile store since it employs some
>     techniques of append only plus eventual compactations.
>     It'd be interesting to have a design document so that we can have
>     a starting point; we usually publish such designs at [2].
>
>     Cheers,
>     Gustavo
>
>     [1] https://issues.jboss.org/browse/ISPN-2940
>     [2] https://github.com/infinispan/infinispan/wiki
>
>     On Thu, May 12, 2016 at 2:26 PM, Cristian Malinescu
>     <cristian.malinescu at gmail.com
>     <mailto:cristian.malinescu at gmail.com>> wrote:
>
>         Hello folks - I would like to implement for my own project a
>         custom cache store for Infinispan using HDFS and using as base
>         line one of the already implemented file stores - SoftIndex
>         and SingleFile.
>         I thought it would be beneficiary if I start and do it
>         directly as contribution to the Infinispan code base, is
>         someone interested to take on this subject and we start
>         brainstorming about how should this task being approached to
>         be sure it gets done smooth, accordingly to the project's
>         community house rules so we don't encounter hassle at the
>         point when we can look at merging in the baseline, avoid
>         potentially double work for same feature etc.
>
>         Kind regards
>         Cristian Malinescu
>
>         https://github.com/Cristian-Malinescu
>         https://www.linkedin.com/in/cristianmalinescu
>
>
>         P.S I went already trough
>         http://infinispan.org/docs/8.2.x/contributing/contributing.html
>         so theoretically I can just start and place a pull request on
>         GitHub but I wanted to be sure you guys are also aware of this
>         plan so we keep in sync and all opinions are taken in
>         consideration and addressed.
>
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-- 
Radim Vansa <rvansa at redhat.com>
JBoss Performance Team