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https://issues.apache.org/jira/browse/HIVE-23085?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17071637#comment-17071637
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Syed Shameerur Rahman commented on HIVE-23085:
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{noformat}
A memory mapped file throws a SIGBUS and kills the whole process when the disk
it is mapped onto is full.
{noformat}
We can still hit this issue even with a single memory mapped disk. Say my disk
space was shared between storing shuffle data (or for any other application)
and storing cache i can run into this issue anytime due to lazy write by OS.
{noformat}
This can be fixed by pre-allocating all the disk space on startup, but that
made startup much much slower (added 7 minutes to startup times).
{noformat}
Yes tried pre-allocating, since there is no fallocate in java i tried with a
hacky way of doing FileChannel.transferTo() from sparse file it took me around
16 mins (consistently) to allocate 256GB of cache with default areanaCount and
maxAlloc size.
> LLAP: Support Multiple NVMe-SSD disk Locations While Using SSD Cache
> --------------------------------------------------------------------
>
> Key: HIVE-23085
> URL: https://issues.apache.org/jira/browse/HIVE-23085
> Project: Hive
> Issue Type: Improvement
> Reporter: Syed Shameerur Rahman
> Assignee: Syed Shameerur Rahman
> Priority: Major
> Labels: pull-request-available
> Fix For: 4.0.0
>
> Attachments: HIVE-23085.01.patch
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Currently we can configure only one SSD location while using SSD cache in
> LLAP. This highly undermines the capacity of some machines to use its disk
> capacity to the fullest. For example *AWS* provides *r5d.4x large* series
> which comes with *2 * 300 GB NVme SSD disk* with the current design only one
> of the mounted *NVme SSD* disk can be used for caching. Hence adding support
> for caching data at multiple ssd mounted locations.
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