You don't need a prime number of nodes in your ring, but it's not a bad idea to it be a multiple of your RF when your cluster is small.
On Tue Dec 09 2014 at 8:29:35 AM Nate Yoder <n...@whistle.com> wrote: > Hi Ian, > > Thanks for the suggestion but I had actually already done that prior to > the scenario I described (to get myself some free space) and when I ran > nodetool cfstats it listed 0 snapshots as expected, so unfortunately I > don't think that is where my space went. > > One additional piece of information I forgot to point out is that when I > ran nodetool status on the node it included all 6 nodes. > > I have also heard it mentioned that I may want to have a prime number of > nodes which may help protect against split-brain. Is this true? If so > does it still apply when I am using vnodes? > > Thanks again, > Nate > > -- > *Nathanael Yoder* > Principal Engineer & Data Scientist, Whistle > 415-944-7344 // n...@whistle.com > > On Tue, Dec 9, 2014 at 7:42 AM, Ian Rose <ianr...@fullstory.com> wrote: > >> Try `nodetool clearsnapshot` which will delete any snapshots you have. I >> have never taken a snapshot with nodetool yet I found several snapshots on >> my disk recently (which can take a lot of space). So perhaps they are >> automatically generated by some operation? No idea. Regardless, nuking >> those freed up a ton of space for me. >> >> - Ian >> >> >> On Mon, Dec 8, 2014 at 8:12 PM, Nate Yoder <n...@whistle.com> wrote: >> >>> Hi All, >>> >>> I am new to Cassandra so I apologise in advance if I have missed >>> anything obvious but this one currently has me stumped. >>> >>> I am currently running a 6 node Cassandra 2.1.1 cluster on EC2 using >>> C3.2XLarge nodes which overall is working very well for us. However, after >>> letting it run for a while I seem to get into a situation where the amount >>> of disk space used far exceeds the total amount of data on each node and I >>> haven't been able to get the size to go back down except by stopping and >>> restarting the node. >>> >>> For example, in my data I have almost all of my data in one table. On >>> one of my nodes right now the total space used (as reported by nodetool >>> cfstats) is 57.2 GB and there are no snapshots. However, when I look at the >>> size of the data files (using du) the data file for that table is 107GB. >>> Because the C3.2XLarge only have 160 GB of SSD you can see why this quickly >>> becomes a problem. >>> >>> Running nodetool compact didn't reduce the size and neither does running >>> nodetool repair -pr on the node. I also tried nodetool flush and nodetool >>> cleanup (even though I have not added or removed any nodes recently) but it >>> didn't change anything either. In order to keep my cluster up I then >>> stopped and started that node and the size of the data file dropped to 54GB >>> while the total column family size (as reported by nodetool) stayed about >>> the same. >>> >>> Any suggestions as to what I could be doing wrong? >>> >>> Thanks, >>> Nate >>> >> >> >
