Is there a specific metric you can recommend? VR
On Wed, Sep 5, 2012 at 9:19 PM, Mohit Anchlia <mohitanch...@gmail.com>wrote: > Cassandra exposes lot of metrics through Jconsole. You might be able to > get some information from Jconsole. > > > On Wed, Sep 5, 2012 at 8:47 PM, Venkat Rama <venkata.s.r...@gmail.com>wrote: > >> Thanks for the quick reply, Mohit. Can we measure/monitor the size of >> Hinted Handoffs? Would it be a good enough indicator of my back log? >> >> Although we know when a network is flaky, we are interested in knowing >> how much data is piling up in local DC that needs to be transferred. >> >> Greatly appreciate your help. >> >> VR >> >> >> On Wed, Sep 5, 2012 at 8:33 PM, Mohit Anchlia <mohitanch...@gmail.com>wrote: >> >>> As far as I know Cassandra doesn't use internal queueing mechanism >>> specific to replication. Cassandra sends the write the remote DC and after >>> that it's upto the tcp/ip stack to deal with buffering. If requests starts >>> to timeout Cassandra would use HH upto certain time. For longer outage you >>> would have to run repair. >>> >>> Also look at tcp/ip tuning parameters that are helpful with your >>> scenario: >>> >>> http://kaivanov.blogspot.com/2010/09/linux-tcp-tuning.html >>> >>> Run iperf and test the latency. >>> >>> On Wed, Sep 5, 2012 at 8:22 PM, Venkat Rama >>> <venkata.s.r...@gmail.com>wrote: >>> >>>> Hi, >>>> >>>> We have multi DC Cassandra ring with 2 DCs setup. We use LOCAL_QUORUM >>>> for writes and reads. The network we have seen between the DC is sometimes >>>> flaky lasting few minutes to few 10 of minutes. >>>> >>>> I wanted to know what is the best way to measure/monitor either the lag >>>> or replication latency between the data centers. Are there any metrics I >>>> can monitor to find the backlog of data that needs to be transferred? >>>> >>>> Thanks in advance. >>>> >>>> VR >>>> >>> >>> >> >
