Vladimir Ozerov created IGNITE-2810:
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Summary: IGFS: Stripe TRASH directory.
Key: IGNITE-2810
URL:
https://issues.apache.org/jira/browse/IGNITE-2810 Project: Ignite
Issue Type: Task
Components: IGFS
Affects Versions: 1.5.0.final
Reporter: Vladimir Ozerov
Priority: Critical
Fix For: 1.7
*Problem*
Currently remove operation on IGFS performs soft-delete which essentially moves a file/dir to a special hidden "TRASH" directory. Later on, special worker inspects this directory and finally removes actual meta and data entities.
As *move* operation requires lock on parent directory, massive removes will lead to high contention on TRASH key, yielding poor performance due to no parallelization.
*Solution*
Let's stripe trash directory. That is, we will create several (e.g. 16) trash directories. When entity is to be removed, we will pick random trash and move entitty there.
Delete worker will have to inspect all these directories.
Note that each node will have to know maximum numbers of trash directories, so it knows how to list it with little or no coordination with other nodes. To achieve this we can expose "trashCount" property to {{FileSystemConfiguration}}. Normally user will not change it. Each node will set up a discovery listener which will track new nodes and will know maximum amount of trashes.
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