Re: Cassandra Rack - Datacenter Load Balancing relations

Thanks, Jon! I just added the AZ for each rack on the right column. However thanks for your reply and clarification. Maybe I should have marked the rack names with RACK-READ and RACK-WRITE to avoid confusion and not use ONE and TWO. What's more, fault-tolerant between with RF=3: A) spread each D

Re: merge two cluster

thank you all. you saved my time and resource. regards osman Get Outlook for Android From: Jon Haddad Sent: Thursday, October 24, 2019 12:13:45 AM To: user@cassandra.apache.org Subject: Re: merge two cluster Probably not beneficial, I wou

Re: merge two cluster

Probably not beneficial, I wouldn't do it. Not a fan of multi-tenancy with Cassandra unless the use cases are so small that your noisy neighbor problem is not very noisy at all. For those cases I don't know what you get from Cassandra other than a cool resume. On Wed, Oct 23, 2019 at 12:41 PM Re

Re: Cassandra Rack - Datacenter Load Balancing relations

Oh, my bad. There was a flood of information there, I didn't realize you had switched to two DCs. It's been a long day. I'll be honest, it's really hard to read your various options as you've intermixed terminology from AWS and Cassandra in a weird way and there's several pages of information he

Re: Cassandra Rack - Datacenter Load Balancing relations

OPTION C or OPTION A? Which one are you referring to? Both have separate DCs to keep the workload separate. - OPTION A) - Node DC RACK AZ 1 read ONE us-east-1a 2 read ONE us-east-1a - 3 read ONE us-east-1a - 4 write TWO us-east-1b 5 write TWO us-east-1b - 6 write TWO us-east-1b

Re: Ram & Space...

pretty clear evidence of a memory leak, tombstone problem (still memory), etc. If this is Apache, then you may need to do some heap dumps and see what is going on (if it is java heap that is OOM'ing, which I suspect. Might want to do some periodic vmstat or equivalent (brute force might be screen

Re: Ram & Space...

We had what sounds like a similar problem with a DSE cluster a little while ago, It was not being used, and had no tables in it. The memory kept rising until it was killed by the oom-killer. We spent along time trying to get to the bottom of the problem, but it suddenly stopped when the develop

Re: Cassandra Rack - Datacenter Load Balancing relations

Personally, I wouldn't ever do this. I recommend separate DCs if you want to keep workloads separate. On Wed, Oct 23, 2019 at 4:06 PM Sergio wrote: > I forgot to comment for > >OPTION C) >1. Node DC RACK AZ 1 read ONE us-east-1a 2 read ONE us-east-1b >2. 3 read ONE us-east

Re: Cassandra Rack - Datacenter Load Balancing relations

I forgot to comment for OPTION C) 1. Node DC RACK AZ 1 read ONE us-east-1a 2 read ONE us-east-1b 2. 3 read ONE us-east-1c 3. 4 write TWO us-east-1a 5 write TWO us-east-1b 4. 6 write TWO us-east-1c I would expect that I need to decrease the Consistency Level in the reads

Re: Cassandra Rack - Datacenter Load Balancing relations

Hi Reid, Thank you very much for clearing these concepts for me. https://community.datastax.com/comments/1133/view.html I posted this question on the datastax forum regarding our cluster that it is unbalanced and the reply was related that the *number of racks should be a multiplier of the replica

Re: Cassandra Rack - Datacenter Load Balancing relations

No, that’s not correct. The point of racks is to help you distribute the replicas, not further-replicate the replicas. Data centers are what do the latter. So for example, if you wanted to be able to ensure that you always had quorum if an AZ went down, then you could have two DCs where one w

Re: Ram & Space...

Thank you. But I have added any tables yet. It’s empty... Sent from Yahoo Mail for iPhone On Tuesday, October 22, 2019, 1:15 AM, Matthias Pfau wrote: Did you check nodetool status and logs? If so, what is reported? Regarding that more and more memory is used. This might be a problem with yo

Re: Cassandra Rack - Datacenter Load Balancing relations

Hi Reid, Thanks for your reply. I really appreciate your explanation. We are in AWS and we are using right now 2 Availability Zone and not 3. We found our cluster really unbalanced because the keyspace has a replication factor = 3 and the number of racks is 2 with 2 datacenters. We want the write

Re: merge two cluster

I haven’t seen much evidence that larger cluster = more performance, plus or minus the statistics of speculative retry. It horizontally scales for storage definitely, and somewhat for connection volume. If anything, per Sean’s observation, you have less ability to have a stable tuning for a pa

Re: Cassandra Rack - Datacenter Load Balancing relations

Datacenters and racks are different concepts. While they don't have to be associated with their historical meanings, the historical meanings probably provide a helpful model for understanding what you want from them. When companies own their own physical servers and have them housed somewhere,

Re: merge two cluster

Sorry, missing question; Actually I'm asking this for performance perspective. At application level both cluster used at the same time and approx same level. Inserted data inserted to both cluster, different parts of course. If I merge two cluster, can I gain some performance improvements? Like

RE: merge two cluster

Beneficial to whom? The apps, the admins, the developers? I suggest that app teams have separate clusters per application. This prevents the noisy neighbor problem, isolates any security issues, and helps when it is time for maintenance, upgrade, performance testing, etc. to not have to coordin

merge two cluster

Hello, I have two cluster and both contains different data sets with different node counts. Would it be beneficial to merge two cluster? Regards, Osman

Cassandra Rack - Datacenter Load Balancing relations

Hello guys! I was reading about https://cassandra.apache.org/doc/latest/architecture/dynamo.html#networktopologystrategy I would like to understand a concept related to the node load balancing. I know that Jon recommends Vnodes = 4 but right now I found a cluster with vnodes = 256 replication fac