fsync?

[Carl Hörberg]

Hi,

running either strace or perf trace i can't see that rabbitmq is issuing any fsync or fdatasync syscalls, even when using publish-confirm (persistent msgs, durable queue). 

The publish confirm page indicated that it should be performed: https://www.rabbitmq.com/confirms.html#publisher-confirms-latency

`sudo perf trace -sp $(ps -C beam.smp --sort cputime -o pid= | tail -1)`

[Karl Nilsson]

The management ui collects fsync rates per node. What do they say?

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Karl Nilsson

[Carl Hörberg]

Ah! Didn't run trace long enough :)

Are consumer ack:s ever fsynced to disk?

On Thursday, July 11, 2019 at 7:13:47 PM UTC+2, kjnilsson wrote:

The management ui collects fsync rates per node. What do they say?

On Thu, 11 Jul 2019 at 18:02, Carl Hörberg <ca...@cloudamqp.com> wrote:

Hi,

running either strace or perf trace i can't see that rabbitmq is issuing any fsync or fdatasync syscalls, even when using publish-confirm (persistent msgs, durable queue). 

The publish confirm page indicated that it should be performed: https://www.rabbitmq.com/confirms.html#publisher-confirms-latency

`sudo perf trace -sp $(ps -C beam.smp --sort cputime -o pid= | tail -1)`

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Karl Nilsson

[Karl Nilsson]

Consumer acks are completely transient. It could be that messages that are fully consumed before the fsync interval negate the need for the fsync. I’d have to check the message store code for that tho. 

Side note: all queue operations will be persisted on disk in the upcoming quorum queue type. 

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Karl Nilsson