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Posted to user@cassandra.apache.org by Meg Mara <mm...@digitalriver.com> on 2019/03/07 16:33:07 UTC

Commit Log sync problems

Hello all,

I recently upgraded from C* 3.0.10 to 3.0.16 and have been receiving these warnings about Commit-Log durations being longer than the configured interval. I don't understand what the problem is, why is the system complaining about such small sync durations? Please advice.

Here are some warnings:


3:WARN  [PERIODIC-COMMIT-LOG-SYNCER] 2019-03-07 13:32:23,785 NoSpamLogger.java:94 - Out of 2750 commit log syncs over the past 274s with average duration of 0.66ms, 4 have exceeded the configured commit interval by an average of 22.50ms



2:WARN  [PERIODIC-COMMIT-LOG-SYNCER] 2019-03-07 13:27:01,214 NoSpamLogger.java:94 - Out of 1 commit log syncs over the past 0s with average duration of 113.00ms, 1 have exceeded the configured commit interval by an average of 13.00ms


Node's cassandra.yaml setting related to Commit-Log:

commit_failure_policy: stop
commitlog_directory: /cassandra/log
commitlog_segment_size_in_mb: 32
commitlog_sync: periodic
commitlog_sync_period_in_ms: 10000
commitlog_total_space_in_mb: 4096

Thank you,
Meg Mara

Re: Commit Log sync problems

Posted by John Sanda <jo...@gmail.com>.

Hi Meg,

I believe that the average duration reported is the total amount of time
that exceeded the interval divided by the number of syncs that exceeded the
interval. Cassandra is not complaining because commit log syncs took 0.66
ms but rather on average 4 commit log syncs 10060 ms.

Cheers,

John

On Thu, Mar 7, 2019 at 11:33 AM Meg Mara <mm...@digitalriver.com> wrote:

> Hello all,
>
>
>
> I recently upgraded from C* 3.0.10 to 3.0.16 and have been receiving these
> warnings about Commit-Log durations being longer than the configured
> interval. I don’t understand what the problem is, why is the system
> complaining about such small sync durations? Please advice.
>
>
>
> Here are some warnings:
>
>
>
> 3:WARN  [PERIODIC-COMMIT-LOG-SYNCER] 2019-03-07 13:32:23,785 NoSpamLogger.java:94 - Out of 2750 commit log syncs over the past 274s with average duration of 0.66ms, 4 have exceeded the configured commit interval by an average of 22.50ms
>
>
>
> 2:WARN  [PERIODIC-COMMIT-LOG-SYNCER] 2019-03-07 13:27:01,214 NoSpamLogger.java:94 - Out of 1 commit log syncs over the past 0s with average duration of 113.00ms, 1 have exceeded the configured commit interval by an average of 13.00ms
>
>
>
>
>
> Node’s cassandra.yaml setting related to Commit-Log:
>
>
>
> commit_failure_policy: stop
>
> commitlog_directory: /cassandra/log
>
> commitlog_segment_size_in_mb: 32
>
> commitlog_sync: periodic
>
> commitlog_sync_period_in_ms: 10000
>
> commitlog_total_space_in_mb: 4096
>
>
>
> Thank you,
>
> *Meg Mara*
>
>
>
>
>
-- 

- John