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Posted to user@cassandra.apache.org by Matthias Pfau <ma...@tutao.de.INVALID> on 2019/10/01 15:16:18 UTC
Multiple compactions to same disk with 3.11.4
Hi there,
we recently upgraded from 2.2 to 3.11.4.
Unfortunately, we are running into problems with the compaction scheduling, now. From time to time, a bunch of compactions (e.g. 6) are scheduled for the same data dir. This makes no sense for spinning disks as it will slow down all compactions and other operations like flushes dramatically.
Has someone else experienced this problem? If so, how did you workaround this? Do you know of an open issue regarding this?
Thanks!
Best,
Matthias
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Re: Multiple compactions to same disk with 3.11.4
Posted by Matthias Pfau <ma...@tutao.de.INVALID>.
You are right, you could set concurrent_compactors to 1 to just allow a single compaction at a time. However, that isn't feasible in our scenario with multiple data dirs as compactions would accumulate.
We wan't to run multiple compactions in parallel but only one per data dir...
Best,
Matthias
Oct 1, 2019, 23:16 by elliott@backblaze.com:
> There's a concurrent_compactors parameter in cassandra.yml that does exactly what the name says. You may also find compaction_throughput_mb_per_sec useful.
>
> On Tue, Oct 1, 2019 at 8:16 AM Matthias Pfau <ma...@tutao.de.invalid> wrote:
>
>> Hi there,
>> we recently upgraded from 2.2 to 3.11.4.
>>
>> Unfortunately, we are running into problems with the compaction scheduling, now. From time to time, a bunch of compactions (e.g. 6) are scheduled for the same data dir. This makes no sense for spinning disks as it will slow down all compactions and other operations like flushes dramatically.
>>
>> Has someone else experienced this problem? If so, how did you workaround this? Do you know of an open issue regarding this?
>>
>> Thanks!
>>
>> Best,
>> Matthias
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: >> user-unsubscribe@cassandra.apache.org <ma...@cassandra.apache.org>
>> For additional commands, e-mail: >> user-help@cassandra.apache.org <ma...@cassandra.apache.org>
>>
>>
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Re: Multiple compactions to same disk with 3.11.4
Posted by Elliott Sims <el...@backblaze.com>.
There's a concurrent_compactors parameter in cassandra.yml that does
exactly what the name says. You may also find
compaction_throughput_mb_per_sec useful.
On Tue, Oct 1, 2019 at 8:16 AM Matthias Pfau <ma...@tutao.de.invalid>
wrote:
> Hi there,
> we recently upgraded from 2.2 to 3.11.4.
>
> Unfortunately, we are running into problems with the compaction
> scheduling, now. From time to time, a bunch of compactions (e.g. 6) are
> scheduled for the same data dir. This makes no sense for spinning disks as
> it will slow down all compactions and other operations like flushes
> dramatically.
>
> Has someone else experienced this problem? If so, how did you workaround
> this? Do you know of an open issue regarding this?
>
> Thanks!
>
> Best,
> Matthias
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@cassandra.apache.org
> For additional commands, e-mail: user-help@cassandra.apache.org
>
>