Well then… I left this on Friday (still running) and came back to it today (Monday) to find the service stopped. So, I blitzed this node from the ring and began anew with a different new node.
I rather suspect the problem was with trying to use Ansible to add these initially - despite the fact that I had a serial limit of 1 and a pause of 90s for starting the service on each new node (based on the time taken when setting up this Cassandra cluster). So…moving forward… It is recommended to only add one new node at a time from what I read. This leads me to: Although I see the new node LOAD is progressing far faster than the previous failure, it is still going to take several hours to move from UJ to UN, which means I’ll be at this all week for the 12 new nodes. If our LOAD per node is around 400-600GB, is there any practical method to speed up adding multiple new nodes which is unlikely to cause problems? After all, in the modern world of big (how big is big?) data, 600G per node is far less than the real BIG big-data. Marc From: Jeff Jirsa <jji...@gmail.com> Sent: Friday, July 8, 2022 5:46 PM To: cassandra <user@cassandra.apache.org> Cc: Bowen Song <bo...@bso.ng> Subject: Re: Adding nodes EXTERNAL Having a node UJ but not sending/receiving other streams is an invalid state (unless 4.0 moved the streaming data out of netstats? I'm not 100% sure, but I'm 99% sure it should be there). It likely stopped the bootstrap process long ago with an error (which you may not have seen), and is running without being in the ring, but also not trying to join the ring. 145GB vs 1.1T could be bits vs bytes (that's a factor of 8), or it could be that you streamed data and compacted it away. Hard to say, but less important - the fact that it's UJ but not streaming means there's a different problem. If it's me, I do this (not guaranteed to work, your mileage may vary, etc): 1) Look for errors in the logs of ALL hosts. In the joining host, look for an exception that stops bootstrap. In the others, look for messages about errors streaming, and/or exceptions around file access. In all of those hosts, check to see if any of them think they're streaming ( nodetool netstats again) 2) Stop the joining host. It's almost certainly not going to finish now. Remove data directories, commitlog directory, saved caches, hints. Wait 2 minutes. Make sure every other host in the cluster sees it disappear from the ring. Then, start it fresh and let it bootstrap again. (you could alternatively try the resumable bootstrap option, but I never use it). On Fri, Jul 8, 2022 at 2:56 AM Marc Hoppins <marc.hopp...@eset.com<mailto:marc.hopp...@eset.com>> wrote: Ifconfig shows RX of 1.1T. This doesn't seem to fit with the LOAD of 145GiB (nodetool status), unless I am reading that wrong...and the fact that this node still has a status of UJ. Netstats on this node shows (other than : Read Repair Statistics: Attempted: 0 Mismatch (Blocking): 0 Mismatch (Background): 0 Pool Name Active Pending Completed Dropped Large messages n/a 0 0 0 Small messages n/a 53 569755545 15740262 Gossip messages n/a 0 288878 2 None of this addresses the issue of not being able to add more nodes. -----Original Message----- From: Bowen Song via user <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Sent: Friday, July 8, 2022 11:47 AM To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> Subject: Re: Adding nodes EXTERNAL I would assume that's 85 GB (i.e. gigabytes) then. Which is approximately 79 GiB (i.e. gibibytes). This still sounds awfully slow - less than 1MB/s over a full day (24 hours). You said CPU and network aren't the bottleneck. Have you checked the disk IO? Also, be mindful with CPU usage. It can still be a bottleneck if one thread uses 100% of a CPU core while all other cores are idle. On 08/07/2022 07:09, Marc Hoppins wrote: > Thank you for pointing that out. > > 85 gigabytes/gibibytes/GIGABYTES/GIBIBYTES/whatever name you care to > give it > > CPU and bandwidth are not the problem. > > Version 4.0.3 but, as I stated, all nodes use the same version so the version > is not important either. > > Existing nodes have 350-400+(choose whatever you want to call a > gigabyte) > > The problem appears to be that adding new nodes is a serial process, which is > fine when there is no data and each node is added within 2minutes. It is > hardly practical in production. > > -----Original Message----- > From: Bowen Song via user > <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> > Sent: Thursday, July 7, 2022 8:43 PM > To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> > Subject: Re: Adding nodes > > EXTERNAL > > > 86Gb (that's gigabits, which is 10.75GB, gigabytes) took an entire day seems > obviously too long. I would check the network bandwidth, disk IO and CPU > usage and find out what is the bottleneck. > > On 07/07/2022 15:48, Marc Hoppins wrote: >> Hi all, >> >> Cluster of 2 DC and 24 nodes >> >> DC1 (RF3) = 12 nodes, 16 tokens each >> DC2 (RF3) = 12 nodes, 16 tokens each >> >> Adding 12 more nodes to DC1: I installed Cassandra (version is the same >> across all nodes) but, after the first node added, I couldn't seem to add >> any further nodes. >> >> I check nodetool status and the newly added node is UJ. It remains this way >> all day and only 86Gb of data is added to the node over the entire day >> (probably not yet complete). This seems a little slow and, more than a >> little inconvenient to only be able to add one node at a time - or at least >> one node every 2 minutes. When the cluster was created, I timed each node >> from service start to status UJ (having a UUID) and it was around 120 >> seconds. Of course there was no data. >> >> Is it possible I have some setting not correctly tuned? >> >> Thanks >> >> Marc
