Hi Marc,
The recycled commit logs functionality was used in very old versions of
Cassandra, but it was removed in version 2.2.0 back in 2015 (so this logic
was removed 10 years ago, and understandably, no one wants to do
archaeological research). The currently supported versions start from 4.0.x.
The idea behind recycled logs was to reuse commit log files to reduce file
system overhead, but in practice, it didn’t work well. It caused issues and
made the implementation unnecessarily complex, so the feature was
eventually removed.
Here’s a good summary article about the Cassandra commit log design, which
also includes a section on recycled logic ("Segment Recycling"):
https://cassandra.apache.org/_/blog/Learn-How-CommitLog-Works-in-Apache-Cassandra.html
However, this knowledge about Cassandra likely won’t help with your current
issue — there’s no guarantee that ScyllaDB shares a similar design in this
area, and any bugs will be specific to ScyllaDB. So, I think the best next
step for you is to contact the ScyllaDB community directly.
You can also check their existing GitHub issues — for example, here’s one
that describes similar symptoms:
https://github.com/scylladb/scylladb/issues/11184
Regards,
Dmitry
On Wed, 2 Jul 2025 at 07:57, Marc Hoppins <marc.hopp...@eset.com> wrote:
> SO CASSANDRA NEVER HAD RECYCLED COMMIT LOGS? If not then I apologise for
> wasting everyone’s time. However if, for previous versions, recycled
> commitlogs were a part of Cassandra then thank you fr not sharing the
> knowledge of a Cassandra item.
>
>
>
> Time to unsubscribe
>
>
>
> *From:* Josh McKenzie <jmcken...@apache.org>
> *Sent:* Tuesday, July 1, 2025 1:47 PM
> *To:* user@cassandra.apache.org
> *Subject:* Re: Recycled-Commitlogs
>
>
>
> EXTERNAL
>
> Can anyone explain WHAT they are?
>
> Yes Marc. The Scylla community. That's what we're trying to tell you.
>
>
>
> As far as anyone on this list seems to think, this isn't related to Apache
> Cassandra.
>
>
>
> On Tue, Jul 1, 2025, at 1:54 AM, Marc Hoppins wrote:
>
> That aside. Can anyone explain WHAT they are? If they were done away with
> in Cassandra then they must have been surplus to requirements. In which
> case, why have them originally? They must have been there for some reason.
>
>
>
> *From:* Josh McKenzie <jmcken...@apache.org>
> *Sent:* Monday, June 30, 2025 4:16 PM
> *To:* user@cassandra.apache.org
> *Subject:* Re: Recycled-Commitlogs
>
>
>
> EXTERNAL
>
> As it is (generally) Cassandra compatible I naturally assumed that these
> items were in both applications.
>
> For future reference - it's "generally CQL API compatible". That's the
> extent of it.
>
>
>
> It's analogous to driving a make/model of one car and taking it to a
> completely different unrelated dealer for maintenance because they're both
> cars. Just because the interface to use them (steering wheel, doors,
> engine, 4 tires) is broadly the same, the internals are wildly different.
>
>
>
> On Sat, Jun 28, 2025, at 11:56 PM, Jeff Jirsa wrote:
>
> Yea we’re not gonna be able to help you
>
>
>
> This sounds like a software defect but it’s not cassandra so we really do
> much
>
>
>
> On 2025/06/27 13:13:17 Marc Hoppins wrote:
>
> > Well, I do have a confession to make. It is actually scyllaDB and the
> latest version. As it is (generally) Cassandra compatible I naturally
> assumed that these items were in both applications.
>
> >
>
> > Marc
>
> >
>
> > From: Jeff Jirsa <jji...@gmail.com>
>
> > Sent: Thursday, June 26, 2025 7:35 PM
>
> > To: user@cassandra.apache.org
>
> > Cc: user@cassandra.apache.org
>
> > Subject: Re: Recycled-Commitlogs
>
> >
>
> > EXTERNAL
>
> > What version of cassandra is this?
>
> >
>
> > Recycling segments was a thing from like 1.1 to 2.2 but really very
> different in modern versions (and cdc / point in time backup mirrors some
> of the concepts around hanging onto segments)
>
> >
>
> > Knowing the version would be super helpful though
>
> >
>
> > Is this … 1.2? 2.0?
>
> >
>
> >
>
> >
>
> > On Jun 26, 2025, at 1:22 AM, guo Maxwell <cclive1...@gmail.com<mailto:
> cclive1...@gmail.com>> wrote:
>
> >
>
> > I guess it comes from the archive of commitlogs ，just guess~~~
>
> >
>
> > But I think we need the cassandra's version and commitlog's
> configuration in cassandra.yaml, and commitlog_archiving.properties to
> determine this.
>
> >
>
> > Marc Hoppins <marc.hopp...@eset.com<mailto:marc.hopp...@eset.com>> 于2025
> 年6月26日周四 16:08写道：
>
> > Hi,
>
> >
>
> > I am not a data person but a Linux admin. One of our nodes has
> thousands of
>
> >
>
> > -rw-r--r-- 1 root root 33554432 Jun 24 15:11
> Recycled-CommitLog-2-67041997483.log
>
> >
>
> > hanging around. Eventually they fill the filesystem. I have searched
> around and can find no mention of these recycled commits.
>
> >
>
> > Can anyone explain what they are for? Can I purge these in some
> graceful fashion with a service restart, a simple deletion, or a complete
> drain/restart of the node?
>
> >
>
> > Thanks
>
> >
>
> > Marc
>
> >
>
>
>
>
>
>
>
--
Dmitry Konstantinov
