Re: data consistency without using nodetool repair
Thanks Jeff, If i run repair every 10 days, then, would there be a chance of losing data by losing one node (data inserted exactly after last repair) ? Sent using Zoho Mail On Sun, 10 Jun 2018 10:14:46 +0430 Jeff Jirsa jji...@gmail.com wrote On Jun 9, 2018, at 10:28 PM, onmstester onmstester onmstes...@zoho.com wrote: I'm using RF=2 (i know it should be at least 3 but i'm short of resources) and WCl=ONE and RCL=ONE in a cluster of 10 nodes in a insert-only scenario. The problem: i dont want to use nodetool repair because it would put hige load on my cluster for a long time, but also i need data consistency and fault tolerance in a way that: if one of my nodes fails: 1. there would be no single record data loss This requires write 1 2. write/read of data would be continued with no problem This requires more replicas in the ring than the number of replicas requires for reads and writes I know that current config won't satisfy No.1, so changed the Write Consistensy Level to ALL and to satisfy No.2, i'm catching exceptions of "1 replicas needed but 2 required", write those records again with WCL = ONE and put them somewhere for rewrite later with WCL=2. Is there anything wrong with this workaround? any better solution (Strong requirements: I can't change the RF, The system should tolerate 1 node failure with no data loss and no read/write failure) Sorta works, but it’s dirty and a lot of edge cases. Depending on the budget and value of data, maybe it’s ok, but I wouldn’t trust it to be good enough for critical use cases The transient replication work that Ariel is doing (https://issues.apache.org/jira/browse/CASSANDRA-14404) will likely benefit you here in 4.0 (but it will require you to run repair).
Re: data consistency without using nodetool repair
> On Jun 9, 2018, at 10:28 PM, onmstester onmstester > wrote: > > > I'm using RF=2 (i know it should be at least 3 but i'm short of resources) > and WCl=ONE and RCL=ONE in a cluster of 10 nodes in a insert-only scenario. > The problem: i dont want to use nodetool repair because it would put hige > load on my cluster for a long time, but also i need data consistency > and fault tolerance in a way that: > if one of my nodes fails: > 1. there would be no single record data loss This requires write > 1 > 2. write/read of data would be continued with no problem > This requires more replicas in the ring than the number of replicas requires for reads and writes > I know that current config won't satisfy No.1, so changed the Write > Consistensy Level to ALL and to satisfy No.2, i'm catching exceptions of > "1 replicas needed but 2 required", write those records again with WCL = ONE > and put them somewhere for rewrite later with WCL=2. > Is there anything wrong with this workaround? any better solution (Strong > requirements: I can't change the RF, The system should tolerate 1 node > failure with no data loss and no read/write failure) Sorta works, but it’s dirty and a lot of edge cases. Depending on the budget and value of data, maybe it’s ok, but I wouldn’t trust it to be good enough for critical use cases The transient replication work that Ariel is doing (https://issues.apache.org/jira/browse/CASSANDRA-14404) will likely benefit you here in 4.0 (but it will require you to run repair).
data consistency without using nodetool repair
I'm using RF=2 (i know it should be at least 3 but i'm short of resources) and WCl=ONE and RCL=ONE in a cluster of 10 nodes in a insert-only scenario. The problem: i dont want to use nodetool repair because it would put hige load on my cluster for a long time, but also i need data consistency and fault tolerance in a way that: if one of my nodes fails: 1. there would be no single record data loss 2. write/read of data would be continued with no problem I know that current config won't satisfy No.1, so changed the Write Consistensy Level to ALL and to satisfy No.2, i'm catching exceptions of "1 replicas needed but 2 required", write those records again with WCL = ONE and put them somewhere for rewrite later with WCL=2. Is there anything wrong with this workaround? any better solution (Strong requirements: I can't change the RF, The system should tolerate 1 node failure with no data loss and no read/write failure) ? Sent using Zoho Mail
