, add
>>>> in the prevelance of HT and you see a lot of 24+ flush writer
>>>> systems in the wild)
>>>>
>>>> No disrespect intended but that default hasn't worked out well at
>>>> all in my exposure to it, and 0.6 has never been worse than t
posure to it, and 0.6 has never been worse than the default yet.
>>> Obviously write patterns, heap configuration, memtable size limits and what
>>> not affect the exact optimal setting and I've rarely had it end up 0.6
>>> after a tuning exercise. I never intended that as a bl
tion, just a starting
one.
_
From: Benedict Elliott Smith bened...@apache.org
Sent: Friday, August 26, 2016 9:40 AM
Subject: Re: Guidelines for configuring Thresholds for Cassandra metrics
To: user@cassandra.apache.org
The default when I wrote it was 0.4 but it
t Elliott Smith <bened...@apache.org>
Sent: Friday, August 26, 2016 9:40 AM
Subject: Re: Guidelines for configuring Thresholds for Cassandra metrics
To: <user@cassandra.apache.org>
The default when I wrote it was 0.4 but it was found this did not saturate
flush writers in JBOD configurat
as a blanket recommendation,
> just a starting one.
>
> _
> From: Benedict Elliott Smith <bened...@apache.org
> <javascript:_e(%7B%7D,'cvml','bened...@apache.org');>>
> Sent: Friday, August 26, 2016 9:40 AM
> Subject: Re: Guidelines for configuring Thres
rarely had it end up 0.6 after a tuning
exercise. I never intended that as a blanket recommendation, just a starting
one.
_
From: Benedict Elliott Smith <bened...@apache.org>
Sent: Friday, August 26, 2016 9:40 AM
Subject: Re: Guidelines for confi
The default when I wrote it was 0.4 but it was found this did not saturate
flush writers in JBOD configurations. Iirc it now defaults to 1/(1+#disks)
which is not a terrible default, but obviously comes out much lower if you
have many disks.
This smaller value behaves better for peak performance,
Forgot the most important thing. LogsERROR you should investigateWARN you
should have a list of known ones. Use case dependent. Ideally you change
configuration accordingly.*PoolCleaner (slab or native) - good indication node
is tuned badly if you see a ton of this. Set
Thomas,
Not all metrics are KPIs and are only useful when researching a specific issue
or after a use case specific threshold has been set.
The main "canaries" I monitor are:* Pending compactions (dependent on the
compaction strategy chosen but 1000 is a sign of severe issues in all cases)*
