On Thu, Sep 22, 2011 at 11:04 PM, Yan Chunlu <springri...@gmail.com> wrote:
> > hi Aaron: > > could you explain more about the issue about repair make space usage going > crazy? > I guess repair defers the compaction progress as it brings a lot of load. For update-heavy workload, the space usage goes higher and higher during repair. > > I am planning to upgrade my cluster from 0.7.4 to 0.8.6, which is because > the repair never works on 0.7.4 for me. > more specifically, > CASSANDRA-2280<https://issues.apache.org/jira/browse/CASSANDRA-2280> > and CASSANDRA-2156 <https://issues.apache.org/jira/browse/CASSANDRA-2156> > . > > > from your description, I really worried about 0.8.6 might make it worse... > > thanks! > > On Thu, Sep 22, 2011 at 7:25 AM, aaron morton <aa...@thelastpickle.com>wrote: > >> How much data is on the nodes in cluster 1 and how much disk space on >> cluster 2 ? Be aware that Cassandra 0.8 has an issue where repair can go >> crazy and use a lot of space. >> >> If you are not regularly running repair I would also repair before the >> move. >> >> The repair after the copy is a good idea but should technically not be >> necessary. If you can practice the move watch the repair to see if much is >> transferred (check the logs). There is always a small transfer, but if you >> see data been transferred for several minutes I would investigate. >> >> When you start a repair it will repair will the other nodes it replicates >> data with. So you only need to run it every RF nodes. Start it one one, >> watch the logs to see who it talks to and then start it on the first node it >> does not talk to. And so on. >> >> Add a snapshot before the clean (repair will also snapshot before it runs) >> >> Scrub is not needed unless you are migrating or you have file errors. >> >> If your cluster is online, consider running the clean every RFth node >> rather than all at once (e.g. 1,4, 7, 10 then 2,5,8,11). It will have less >> impact on clients. >> >> Cheers >> >> ----------------- >> Aaron Morton >> Freelance Cassandra Developer >> @aaronmorton >> http://www.thelastpickle.com >> >> On 22/09/2011, at 10:27 AM, Philippe wrote: >> >> Hello, >> We're currently running on a 3-node RF=3 cluster. Now that we have a >> better grip on things, we want to replace it with a 12-node RF=3 cluster of >> "smaller" servers. So I wonder what the best way to move the data to the new >> cluster would be. I can afford to stop writing to the current cluster for >> whatever time is necessary. Has anyone written up something on this subject >> ? >> >> My plan is the following (nodes in cluster 1 are node1.1->1.3, nodes in >> cluster 2 are node2.1->2.12) >> >> - stop writing to current cluster & drain it >> - get a snapshot on each node >> - Since it's RF=3, each node should have all the data, so assuming I >> set the tokens correctly I would move the snapshot from node1.1 to >> node2.1, >> 2.2, 2.3 and 2.4 then node1.2->node2.5,2.6,2.,2.8, etc. This is because >> the >> range for node1.1 is now spread across 2.1->2.4 >> - Run repair & clean & scrub on each node (more or less in //) >> >> What do you think ? >> Thanks >> >> >> >
