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https://issues.apache.org/jira/browse/HBASE-15248?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15141671#comment-15141671
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stack commented on HBASE-15248:
-------------------------------

Matteo noted that we should be clear that we are not trying to write perfectly 
aligned 4k pages on a device in this issue (hdfs and actual fs are in the way).

> One block, one seek: a.k.a BLOCKSIZE 4k should result in 4096 bytes on disk
> ---------------------------------------------------------------------------
>
>                 Key: HBASE-15248
>                 URL: https://issues.apache.org/jira/browse/HBASE-15248
>             Project: HBase
>          Issue Type: Sub-task
>          Components: BucketCache
>            Reporter: stack
>
> Chatting w/ a gentleman named Daniel Pol who is messing w/ bucketcache, he 
> wants blocks to be the size specified in the configuration and no bigger. His 
> hardware set ups fetches pages of 4k and so a block that has 4k of payload 
> but has then a header and the header of the next block (which helps figure 
> whats next when scanning) ends up being 4203 bytes or something, and this 
> then then translates into two seeks per block fetch.
> This issue is about what it would take to stay inside our configured size 
> boundary writing out blocks.
> If not possible, give back better signal on what to do so you could fit 
> inside a particular constraint.



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