Aaron, thanks for your feedback. .125 num_tokens: 256 # initial_token:
.126 num_tokens: 256 #initial_token: .127 num_tokens: 256 # initial_token: This all looks correct. So when you say to do this with a "clean" setup, what are you asking me to do? Is it enough to blow away /var/lib/cassandra and reload the data? Also destroy my Cassandra install (which is just un-tar) and reinstall from nothing? Stephen Thompson Wells Fargo Corporation Internet Authentication & Fraud Prevention 704.427.3137 (W) | 704.807.3431 (C) This message may contain confidential and/or privileged information, and is intended for the use of the addressee only. If you are not the addressee or authorized to receive this for the addressee, you must not use, copy, disclose, or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation. From: aaron morton [mailto:aa...@thelastpickle.com] Sent: Monday, February 11, 2013 12:51 PM To: user@cassandra.apache.org Subject: Re: unbalanced ring The tokens are not right, not right at all. Some are too short and some are too tall. More technically they do not appear to be randomly arranged. The tokens for the .125 node all start with -3, the 126 node only has negative tokens and the 127 node mostly has positive tokens. Check that on each node the initial_token yaml setting is commented out, and that num_tokens is set to 256. If you can reproduce this fault with a clean setup please raise a ticket at https://issues.apache.org/jira/browse/CASSANDRA Cheers ----------------- Aaron Morton Freelance Cassandra Developer New Zealand @aaronmorton http://www.thelastpickle.com On 8/02/2013, at 10:36 AM, stephen.m.thomp...@wellsfargo.com<mailto:stephen.m.thomp...@wellsfargo.com> wrote: I found when I tried to do queries after sending this that although it shows a ton of data, it would no longer return ANYTHING for any query ... always 0 rows. So something was severely hosed. I blew away the data and reloaded from database ... the data set is a little smaller than before. It shows up somewhat more balanced, although I'm still curious why the third node is so much smaller than the first two. [root@Config3482VM1 apache-cassandra-1.2.1]# bin/nodetool status Datacenter: 28 ============== Status=Up/Down |/ State=Normal/Leaving/Joining/Moving -- Address Load Tokens Owns (effective) Host ID Rack UN 10.28.205.125 994.89 MB 255 33.7% 3daab184-61f0-49a0-b076-863f10bc8c6c 205 UN 10.28.205.126 966.17 MB 256 99.9% 55bbd4b1-8036-4e32-b975-c073a7f0f47f 205 UN 10.28.205.127 699.79 MB 257 66.4% d240c91f-4901-40ad-bd66-d374a0ccf0b9 205 [root@Config3482VM1 apache-cassandra-1.2.1]# And yes, that is the entire content of the output from the status call, unedited. I have attached the output from nodetool ring. To answer a couple of the questions from below from Eric: * One data center (28)? One rack (205)? Three nodes? Yes, that's right. We're just doing a proof of concept at the moment so this is three VMWare servers. * How many keyspaces, and what are the replication strategies? There is one keyspace, and it has only one CF at this point. [default@KEYSPACE_NAME] describe; Keyspace: KEYSPACE_NAME: Replication Strategy: org.apache.cassandra.locator.NetworkTopologyStrategy Durable Writes: true Options: [28:2] * TL;DR What Aaron Said(tm) In the absence of rack/dc aware replication, your allocation is suspicious. I'm not sure what you mean by this. Steve -----Original Message----- From: Eric Evans [mailto:eev...@acunu.com<http://acunu.com>] Sent: Thursday, February 07, 2013 9:56 AM To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> Subject: Re: unbalanced ring On Wed, Feb 6, 2013 at 2:02 PM, <stephen.m.thomp...@wellsfargo.com<mailto:stephen.m.thomp...@wellsfargo.com>> wrote: > Thanks Aaron. I ran the cassandra-shuffle job and did a rebuild and > compact on each of the nodes. > > > > [root@Config3482VM1 apache-cassandra-1.2.1]# bin/nodetool status > > Datacenter: 28 > > ============== > > Status=Up/Down > > |/ State=Normal/Leaving/Joining/Moving > > -- Address Load Tokens Owns (effective) Host ID > Rack > > UN 10.28.205.125 1.7 GB 255 33.7% > 3daab184-61f0-49a0-b076-863f10bc8c6c 205 > > UN 10.28.205.126 591.44 MB 256 99.9% > 55bbd4b1-8036-4e32-b975-c073a7f0f47f 205 > > UN 10.28.205.127 112.28 MB 257 66.4% > d240c91f-4901-40ad-bd66-d374a0ccf0b9 205 Sorry, I have to ask, Is this the complete output? Have you perhaps sanitized it in some way? It seems like there is some piece of missing context here. Can you tell us: * Is this a cluster that was upgraded to virtual nodes (that would include a 1.2.x cluster initialized with one token per node, and num_tokens set after the fact). If so, what did the initial token map look like? * Was initial_token used at any point along the way (either to supply a single token, or csv list of them), on any or all of the nodes in this cluster, at any time? * One data center (28)? One rack (205)? Three nodes? * How many keyspaces, and what are the replication strategies? * What does the full output of `nodetool ring' look like now? Can you attach it? > So this is a little better. At last node 3 has some content, but they > are still far from balanced. If I am understand this correctly, this > is the distribution I would expect if the tokens were set at 15/5/1 > rather than equal. As configured, I would expect roughly equal > amounts of data on each node. Is that right? Do you have any > suggestions for what I can look at to get there? Shuffle should only be required if you started out with 1-token-per-node. In that case, your existing ranges are evenly divided num_tokens ways, and so should be exceptionally consistent with one another (assuming of course that the existing ranges were evenly sized). The shuffle op merely "shuffles" the ranges you have to (random )other nodes in the cluster. If this cluster were started from scratch with num_tokens = 256, then a total of 768 tokens would have been randomly generated from within the murmur3 hash-space. Random assignment isn't perfect, but with 768 tokens (256 per), it should work out to be reasonably close on average. TL;DR What Aaron Said(tm) In the absence of rack/dc aware replication, your allocation is suspicious. > I have about 11M rows of data in this keyspace and none of them are > exceptionally long ... it's data pulled from Oracle and didn't include > any BLOB, etc. [ ... ] > From: aaron morton [mailto:aa...@thelastpickle.com] > Sent: Tuesday, February 05, 2013 3:41 PM > To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> > Subject: Re: unbalanced ring > > > > Use nodetool status with vnodes > http://www.datastax.com/dev/blog/upgrading-an-existing-cluster-to-vnod > es > > > > The different load can be caused by rack affinity, are all the nodes > in the same rack ? Another simple check is have you created some very big > rows? > On 6/02/2013, at 8:40 AM, > stephen.m.thomp...@wellsfargo.com<mailto:stephen.m.thomp...@wellsfargo.com> > wrote: > > > > So I have three nodes in a ring in one data center. My configuration > has > num_tokens: 256 set andinitial_token commented out. When I look at > the ring, it shows me all of the token ranges of course, and basically > identical data for each range on each node. Here is the Cliff's Notes > version of what I see: > > > > [root@Config3482VM2 apache-cassandra-1.2.0]# bin/nodetool ring > > > > Datacenter: 28 > > ========== > > Replicas: 1 > > > > Address Rack Status State Load Owns > Token > > > 9187343239835811839 > > 10.28.205.125 205 Up Normal 2.85 GB 33.69% > -3026347817059713363 > > 10.28.205.125 205 Up Normal 2.85 GB 33.69% > -3026276684526453414 > > 10.28.205.125 205 Up Normal 2.85 GB 33.69% > -3026205551993193465 > > (etc) > > 10.28.205.126 205 Up Normal 1.15 GB 100.00% > -9187343239835811840 > > 10.28.205.126 205 Up Normal 1.15 GB 100.00% > -9151314442816847872 > > 10.28.205.126 205 Up Normal 1.15 GB 100.00% > -9115285645797883904 > > (etc) > > 10.28.205.127 205 Up Normal 69.13 KB 66.30% > -9223372036854775808 > > 10.28.205.127 205 Up Normal 69.13 KB 66.30% > 36028797018963967 > > 10.28.205.127 205 Up Normal 69.13 KB 66.30% > 72057594037927935 > > (etc) > > > > So at this point I have a number of questions. The biggest question is of > Load. Why does the .125 node have 2.85 GB, .126 has 1.15 GB, and .127 > has only 0.000069 GB? These boxes are all comparable and all > configured identically. > > > > partitioner: org.apache.cassandra.dht.Murmur3Partitioner > > > > I'm sorry to ask so many questions - I'm having a hard time finding > documentation that explains this stuff. -- Eric Evans Acunu | http://www.acunu.com | @acunu <ring.txt>
