We have written a large amount of data to Cassandra from another database. When writing the client was set to write local quorum.
A few days after writing the data, we tried this on cassandra-cli get example['key'][123]; Value was not found Elapsed time: 50 msec(s). Then a bit later get datapoints['key'][123]; => (column=123, value=456, timestamp=1354095697384001) Elapsed time: 77 msec(s). We assume this is to do with replication, with the first read causing a repair, but there dosen't seem to be any way of seeing what date is on which servers to validate. I have not had a chance yet of trying the previous suggestion. Owen On 3 December 2012 20:18, aaron morton <aa...@thelastpickle.com> wrote: > When reading, sometimes the data is there, > sometimes it is not, which we think is a replication issue, even > though we have left it plenty of time after the writes. > > Can you provide some more information on this ? > Are you talking about writes to one DC and reads from another ? > > Cheers > > ----------------- > Aaron Morton > Freelance Cassandra Developer > New Zealand > > @aaronmorton > http://www.thelastpickle.com > > On 4/12/2012, at 6:45 AM, Шамим <sre...@yandex.ru> wrote: > > Yes, it's should be. dc1:3 means u have 3 copy of every piece of row, with > local quorum you always get a good consistency from 3 nodes. > First you have to calculate token for data center dc1 and add offset 100 to > token for the second data center which will resolve your problem. After > creating the keyspace you can run the nodetool command with ring KEYSPACE > NAME which should show u the load for every node as 33% > Hope it will help u > Shamim > > Hi Shamim > > I have read a bit about the Tokens. I understand how that could effect > the data distribution at first, but I don't understand if we have > specified Options: [dc1:3, dc2:3], surely after a while all the data > will be on every server? > > Thanks, > > Owen > > On 3 December 2012 14:06, Шамим <sre...@yandex.ru> wrote: > > Hello Owen, > Seems you did not configure token for all nodes correctly. See the section > Calculating Tokens for multiple data centers here > http://www.datastax.com/docs/0.8/install/cluster_init > > Best regards > Shamim > --- > On Mon, Dec 3, 2012 at 4:42 PM, Owen Davies <cassan...@obduk.com> wrote: > > We have a 2 data center test cassandra setup running, and are writing > to it using LOCAL_QUORUM. When reading, sometimes the data is there, > sometimes it is not, which we think is a replication issue, even > though we have left it plenty of time after the writes. > > We have the following setup: > > cassandra -v: 1.1.6 > > cassandra.yaml > ----------------------- > > cluster_name: something > > endpoint_snitch: PropertyFileSnitch > > cassandra-topology.properties > -------------------------------------------- > 192.168.1.1=dc1:rack1 > 192.168.1.2=dc1:rack1 > 192.168.1.3=dc1:rack1 > > 192.168.2.1=dc2:rack1 > 192.168.2.2=dc2:rack1 > 192.168.2.3=dc3:rack1 > > default=nodc:norack > > cassandra-cli > -------------------- > Keyspace: example: > Replication Strategy: org.apache.cassandra.locator.NetworkTopologyStrategy > Durable Writes: true > Options: [dc1:3, dc2:3] > > nodetool ring > ------------------- > > Address DC Rack Status State Load > Effective-Ownership Token > > 159447687142037741049740936276011715300 > 192.168.1.2 dc1 rack1 Up Normal 111.17 GB > 100.00% 67165620003619490909052924699950283577 > 192.168.1.1 dc1 rack1 Up Normal 204.57 GB > 100.00% 71045951808949151217931264995073558408 > 192.168.2.1 dc2 rack1 Up Normal 209.92 GB > 100.00% 107165019770579893816561717940612111506 > 192.168.1.3 dc1 rack1 Up Normal 209.92 GB > 100.00% 114165363957966360026729000065495595953 > 192.168.2.3 dc2 rack1 Up Normal 198.22 GB > 100.00% 147717787092318068320268200174271353451 > 192.168.2.2 dc2 rack1 Up Normal 179.31 GB > 100.00% 159447687142037741049740936276011715300 > > Does anyone have any ideas why every server does not have the same > amount of data on? > > Thanks, > > Owen > > > > -- > >
