Aaron, here is the source: http://www.datastax.com/docs/0.8/cluster_architecture/cluster_planning
Thanks! On Sun, Jul 21, 2013 at 4:57 PM, aaron morton <aa...@thelastpickle.com>wrote: > > Wouldn't this make Writes disk-bound then? I think the documentation may > have been a bit misleading then "Insert-heavy workloads will actually be > CPU-bound in Cassandra before being memory-bound"? > What is the source of the quote ? > > Cheers > ----------------- > Aaron Morton > Cassandra Consultant > New Zealand > > @aaronmorton > http://www.thelastpickle.com > > On 21/07/2013, at 4:27 AM, Mohammad Hajjat <haj...@purdue.edu> wrote: > > > Thanks/Shukran, Jon! :) > > > > Wouldn't this make Writes disk-bound then? I think the documentation may > have been a bit misleading then "Insert-heavy workloads will actually be > CPU-bound in Cassandra before being memory-bound"? > > > > > > > > > > On Sat, Jul 20, 2013 at 12:12 PM, Jonathan Haddad < > jonathan.had...@gmail.com> wrote: > > Everything is written to the commit log. In the case of a crash, > cassandra recovers by replaying the log. > > > > > > On Sat, Jul 20, 2013 at 9:03 AM, Mohammad Hajjat <haj...@purdue.edu> > wrote: > > Patricia, > > > > Thanks for the info. So are you saying that the *whole* data is being > written on disk in the commit log, not just some sort of a summary/digest? > > I'm writing 10MB objects and I'm noticing high latency (250 milliseconds > even with ANY consistency), so I guess that explains my high delays? > > > > Thanks, > > Mohammad > > > > > > On Fri, Jul 19, 2013 at 2:17 PM, Patricia Gorla < > gorla.patri...@gmail.com> wrote: > > Kanwar, > > > > This is because writes are appends to the commit log, which is stored on > disk, not memory. The commit log is then flushed to the memtable (in > memory), before being written to an sstable on disk. > > > > So, most of the actions in sending out a write are writing to disk. > > > > Also see: http://www.datastax.com/docs/1.2/dml/about_writes > > > > Patricia > > > > > > On Fri, Jul 19, 2013 at 1:05 PM, Kanwar Sangha <kan...@mavenir.com> > wrote: > > “Insert-heavy workloads will actually be CPU-bound in Cassandra before > being memory-bound” > > > > > > > > Can someone explain why the internals of why writes are CPU bound ? > > > > > > > > > > > > > > > > > > > > -- > > Mohammad Hajjat > > Ph.D. Student > > Electrical and Computer Engineering > > Purdue University > > > > > > > > > > -- > > Mohammad Hajjat > > Ph.D. Student > > Electrical and Computer Engineering > > Purdue University > > -- *Mohammad Hajjat* *Ph.D. Student* *Electrical and Computer Engineering* *Purdue University*
