Hey Colin, Thanks for the review!
I am also skeptical that much space can be reclaimed via compaction as detailed in the limitations section of the KIP. In my head there are two ways to get out of the saturated state - configure more aggressive retention and delete topics. I wasn't aware that KRaft deletes topics marked for deletion on startup if the disks occupied by those partitions are full - I will check it out, thank you for the information! On the retention side, I believe there is still a benefit in keeping the broker up and responsive - in my experience, people first try to reduce the data they have and only when that also does not work they are okay with sacrificing all of the data. Let me know your thoughts! Best, Christo On Fri, 2 Jun 2023 at 20:09, Colin McCabe <cmcc...@apache.org> wrote: > Hi Christo, > > We're not adding new stuff to ZK at this point (it's deprecated), so it > would be good to drop that from the design. > > With regard to the "saturated" state: I'm skeptical that compaction could > really move the needle much in terms of freeing up space -- in most > workloads I've seen, it wouldn't. Compaction also requires free space to > function as well. > > So the main benefit of the "satured" state seems to be enabling deletion > on full disks. But KRaft mode already has most of that benefit. Full disks > (or, indeed, downed brokers) don't block deletion on KRaft. If you delete a > topic and then bounce the broker that had the disk full, it will delete the > topic directory on startup as part of its snapshot load process. > > So I'm not sure if we really need this. Maybe we should re-evaluate once > we have JBOD + KRaft. > > best, > Colin > > > On Mon, May 22, 2023, at 02:23, Christo Lolov wrote: > > Hello all! > > > > I would like to start a discussion on KIP-928: Making Kafka resilient to > > log directories becoming full which can be found at > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-928%3A+Making+Kafka+resilient+to+log+directories+becoming+full > > . > > > > In summary, I frequently run into problems where Kafka becomes > unresponsive > > when the disks backing its log directories become full. Such > > unresponsiveness generally requires intervention outside of Kafka. I have > > found it to be significantly nicer of an experience when Kafka maintains > > control plane operations and allows you to free up space. > > > > I am interested in your thoughts and any suggestions for improving the > > proposal! > > > > Best, > > Christo >
