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https://issues.apache.org/jira/browse/HBASE-25524?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17349651#comment-17349651
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Rahul Kumar edited comment on HBASE-25524 at 5/22/21, 10:07 AM:
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> but we can use the FSDataInputStreamWrapper we maintain to read the file and
>then check if the read happened via SCR / zero copy
[~busbey] If the canary file isn't written/persistent local to the system,
wouldn't that fail our purpose of ensuring SCR is working ? Sorry, looks like I
am missing some context here.
was (Author: rkrahul324):
> but we can use the FSDataInputStreamWrapper we maintain to read the file and
>then check if the read happened via SCR / zero copy
[Sean
Busbey|applewebdata://172D0324-EBDD-4FCD-9F17-B39723DE1DCC/jira/secure/ViewProfile.jspa?name=busbey]
If the canary file isn't written/persistent local to the system, wouldn't
that fail our purpose of ensuring SCR is working ? Sorry, looks like I am
missing some context here.
> Region Servers should give some indication that short-circuit reads are
> configured properly and working
> -------------------------------------------------------------------------------------------------------
>
> Key: HBASE-25524
> URL: https://issues.apache.org/jira/browse/HBASE-25524
> Project: HBase
> Issue Type: Improvement
> Components: Performance, regionserver, Usability
> Affects Versions: 3.0.0-alpha-1, 2.3.0, 2.4.0
> Reporter: Nick Dimiduk
> Assignee: Rahul Kumar
> Priority: Major
>
> Going through the exercise of confirming short-circuit reads turns out to be
> quite a chore. 2.3.0 added a new metric, but metrics only get tickled when
> there's traffic that happens to use the feature. This is not very convenient
> for an operator who has taken a cluster out of service for maintenance.
> It would be nice if the rs process could perform some test and emitted some
> confirmation of the status of this otherwise transparent feature. After
> confirmation, it could light up a boolean metric value and/or add mention of
> it to the info page.
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