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https://issues.apache.org/jira/browse/JCR-926?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12524022
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Thomas Mueller commented on JCR-926:
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Hi,
Theoretically the data store could be split to different directories / hard
drives. Content that is accessed more often could be moved to a faster disk,
and less used data could eventually be moved to slower / cheaper disk. That
would be an extension of the 'memory hierarchy' (see also
http://en.wikipedia.org/wiki/Memory_hierarchy). Of course this wouldn't limit
the space used per workspace, but would improve system performance if done
right. Maybe we need to do that anyway in the near future to better support
solid state disk.
Workspace usage: I'm not sure what solution would be the best for your use
case. Maybe this would better be discussed in a separate thread. See also
http://wiki.apache.org/jackrabbit/DavidsModel#head-ca639e0ee110b80e8277a50f9b9de092b5d86427
> Global data store for binaries
> ------------------------------
>
> Key: JCR-926
> URL: https://issues.apache.org/jira/browse/JCR-926
> Project: Jackrabbit
> Issue Type: New Feature
> Components: core
> Reporter: Jukka Zitting
> Attachments: dataStore.patch, DataStore.patch, DataStore2.patch,
> dataStore3.patch, dataStore4.zip, dataStore5-garbageCollector.patch,
> internalValue.patch, ReadWhileSaveTest.patch
>
>
> There are three main problems with the way Jackrabbit currently handles large
> binary values:
> 1) Persisting a large binary value blocks access to the persistence layer for
> extended amounts of time (see JCR-314)
> 2) At least two copies of binary streams are made when saving them through
> the JCR API: one in the transient space, and one when persisting the value
> 3) Versioining and copy operations on nodes or subtrees that contain large
> binary values can quickly end up consuming excessive amounts of storage space.
> To solve these issues (and to get other nice benefits), I propose that we
> implement a global "data store" concept in the repository. A data store is an
> append-only set of binary values that uses short identifiers to identify and
> access the stored binary values. The data store would trivially fit the
> requirements of transient space and transaction handling due to the
> append-only nature. An explicit mark-and-sweep garbage collection process
> could be added to avoid concerns about storing garbage values.
> See the recent NGP value record discussion, especially [1], for more
> background on this idea.
> [1]
> http://mail-archives.apache.org/mod_mbox/jackrabbit-dev/200705.mbox/[EMAIL
> PROTECTED]
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