Ashish, *> So, with this speed, is it possible in cassandra to perform asynchronous write in new DC(India)? * Nope, however your consistency level choice on writes is the main control for this. You write to the local DC with LOCAL_* consistency would make the acks on write to the remote DC not needed for your app. If your WAN is unstable then you will (assuming it's enabled) have hints to handle intermittent blips and if it is out for extended periods of time then you will need to repair your data.
*> Also, is there any compression technique which cassandra applies while transferring data across DC?* Yes. In the cassandra.yaml there internode_compression config. This default to all, but can be used to selectively only compress cross-DC traffic if you like. You can also look at tuning inter_dc_stream_throughput_outbound_megabits_per_sec and/or stream_throughput_outbound_megabits_per_sec or look at shaping the traffic at the network level (never done this on GCP so not sure how) *> All 3 coordinator nodes in US will be responsible for transfering 1/3rd data to new DC. So, at peak time only 1GB/3 is what each node has to sync.* *Please let me know is my assumption right? If yes, what will happen if data generated in commit log per node increase to 3 GB per minute tomorrow.* Not quite following your assumption - however Cassandra will handle failure/bottlenecks on the WAN and can recover/repair if the failure is pretty serious. Good luck! Johnny On Wed, 27 Jan 2021 at 03:37, MyWorld <timeplus.1...@gmail.com> wrote: > Hi, > We have a cluster with one Data Center of 3 nodes in GCP-US(RF=3).Current > apache cassandra version 3.11.6. We are planning to add one new Data Center > of 3 nodes in GCP-India. > > At peak hours, files generation in commit logs at GCP-US side on one node > is around 1 GB per minute (i.e 17+ mbps). > > Currently the file transfer speed from GCP US to India is 9 mbps. > > So, with this speed, is it possible in cassandra to perform asynchronous > write in new DC(India)? > Also, is there any compression technique which cassandra applies while > transferring data across DC? > > *My assumption *: All 3 coordinator nodes in US will be responsible for > transfering 1/3rd data to new DC. So, at peak time only 1GB/3 is what each > node has to sync. > Please let me know is my assumption right? If yes, what will happen if > data generated in commit log per node increase to 3 GB per minute tomorrow. > > Regards, > Ashish > > -- -- The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. www.digitalis.io <http://www.digitalis.io>
