Well, I personally don't like RF=2. It means if you're using CL=QUORUM and a node goes down, you're going to have a bad time. (downtime) If you're using CL=ONE then you'd be ok. However, I am not wild about losing a node and having only 1 copy of my data available in prod.
On Tue Dec 09 2014 at 8:40:37 AM Nate Yoder <n...@whistle.com> wrote: > Thanks Jonathan. So there is nothing too idiotic about my current set-up > with 6 boxes each with 256 vnodes each and a RF of 2? > > I appreciate the help, > Nate > > > > -- > *Nathanael Yoder* > Principal Engineer & Data Scientist, Whistle > 415-944-7344 // n...@whistle.com > > On Tue, Dec 9, 2014 at 8:31 AM, Jonathan Haddad <j...@jonhaddad.com> wrote: > >> 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 >>>>> >>>> >>>> >>> >
