Re: Large number of tiny sstables flushed constantly

2021-08-13 Thread Jiayong Sun
Hi Jeff, The cluster was build with 2.1 and has been upgraded to 3.11. It's using "num_token: 64"  and RF=3 for all keyspaces in all DCs.There are over 100 nodes in each of 6 rings.I don't see any messages of the repair/steaming in system.log so this shouldn't be related with the repair.I can

Re: Large number of tiny sstables flushed constantly

2021-08-13 Thread Jiayong Sun
Hi Bowen, There are many nodes having this issue and some of them repeatedly having it.Replacing a node by wiping out everything and streaming in good shape of sstables would work, but if we don't know the root cause the node would be in the bad shape again.Yes, we know the reaper repair

Re: Large number of tiny sstables flushed constantly

2021-08-13 Thread Jiayong Sun
Hi Bowen, We do have reaper repair job scheduled periodically and it can take days even weeks to complete one round of repair due to large number of rings/nodes. However, we have paused the repair since we are facing this issue.We do not use the MV in this cluster.There is major table taking

Re: Large number of tiny sstables flushed constantly

2021-08-13 Thread Bowen Song
Hi Jiayong, I'm sorry to hear that. I did not know many nodes were/are experiencing the same issue. A bit of dig in the source code indicates the log below comes from the ColumnFamilyStore.logFlush() method. DEBUG [NativePoolCleaner] ColumnFamilyStore.java:932 - Enqueuing flush of

Re: Large number of tiny sstables flushed constantly

2021-08-13 Thread Jeff Jirsa
A very large cluster using vnodes will cause lots of small sstables to stream in during repair if the cluster is out of sync. This is one of the reasons that the default number of vnodes was decreased in 4.0. How many nodes in the cluster, how many DCs, how many vnodes per node, and how many

Re: Large number of tiny sstables flushed constantly

2021-08-13 Thread Bowen Song
Hi Jiayong, That doesn't really match the situation described in the SO question. I suspected it was related to repairing a table with MV and large partitions, but based on the information you've given, I was clearly wrong. A few hundreds MB partitions is not exactly unusual, I don't see

Re: Large number of tiny sstables flushed constantly

2021-08-13 Thread Bowen Song
Hi Jiayong, Sorry I didn't make it clear in my previous email. When I commented on the RAID0 setup, it was only a comment on the RAID0 setup vs JBOD, and that was not in relation to the SSTable flushing issue. The part of my previous email after the "On the frequent SSTable flush issue" line