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https://issues.apache.org/jira/browse/OAK-7083?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16375021#comment-16375021
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Matt Ryan commented on OAK-7083:
--------------------------------

[~amitjain] [~chetanm]
{quote}Is it a requirement that the Primary should not delete blobs used by the 
Secondary? 
{quote}
I don't know if that was spelled out as a requirement.  It seems like an 
undesirable situation to have the Primary delete blobs that are still being 
referenced by the Secondary.  For the specific use case this was meant to 
address (production system and staging system sharing the data store) it may be 
acceptable that the secondary system have missing blobs, although not ideal.  
But it certainly limits the usability of the system for other similar use cases.
{quote}it would still be strange for the Primary (a Production system) to have 
to co-ordinate GC with a Secondary (staging or a test system) which it has no 
knowledge about.
{quote}
Agreed.

> CompositeDataStore - ReadOnly/ReadWrite Delegate Support
> --------------------------------------------------------
>
>                 Key: OAK-7083
>                 URL: https://issues.apache.org/jira/browse/OAK-7083
>             Project: Jackrabbit Oak
>          Issue Type: New Feature
>          Components: blob, blob-cloud, blob-cloud-azure, blob-plugins
>            Reporter: Matt Ryan
>            Assignee: Matt Ryan
>            Priority: Major
>
> Support a specific composite data store use case, which is the following:
> * One instance uses no composite data store, but instead is using a single 
> standard Oak data store (e.g. FileDataStore)
> * Another instance is created by snapshotting the first instance node store, 
> and then uses a composite data store to refer to the first instance's data 
> store read-only, and refers to a second data store as a writable data store
> One way this can be used is in creating a test or staging instance from a 
> production instance.  At creation, the test instance will look like 
> production, but any changes made to the test instance do not affect 
> production.  The test instance can be quickly created from production by 
> cloning only the node store, and not requiring a copy of all the data in the 
> data store.



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