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https://issues.apache.org/jira/browse/CASSANDRA-5863?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15255538#comment-15255538
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Benedict commented on CASSANDRA-5863:
-------------------------------------
bq. I've double checked with multiple familiar people that most of the
modern/popular filesystems (NTFS, ext*, xfs etc.) already have support for that
It's worth double checking what that support entails - in XFS (since I happen
to have recently read the spec), such a gap would be represented by introducing
a b+-tree, rather than a single-continuous allocation (on the assumption
contiguous space was available on disk in the location of the first inode).
This could result in multiple levels of inode, such that a random seek into the
file (our usual modus operandi) could incur many more disk accesses than
previously was the case.
> In process (uncompressed) page cache
> ------------------------------------
>
> Key: CASSANDRA-5863
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5863
> Project: Cassandra
> Issue Type: Sub-task
> Reporter: T Jake Luciani
> Assignee: Branimir Lambov
> Labels: performance
> Fix For: 3.x
>
>
> Currently, for every read, the CRAR reads each compressed chunk into a
> byte[], sends it to ICompressor, gets back another byte[] and verifies a
> checksum.
> This process is where the majority of time is spent in a read request.
> Before compression, we would have zero-copy of data and could respond
> directly from the page-cache.
> It would be useful to have some kind of Chunk cache that could speed up this
> process for hot data, possibly off heap.
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