Hi Bhuvan,
From the following link,it doesn't suggest us to use RAC and it looks
reasonable.
http://www.datastax.com/dev/blog/multi-datacenter-replication
Defining one rack for the entire cluster is the simplest and most common
implementation. Multiple racks should be avoided for the following reasons:
• Most users tend to ignore or forget rack requirements that
state racks should be in an alternating order to allow the data to get
distributed safely and appropriately.
• Many users are not using the rack information effectively by
using a setup with as many racks as they have nodes, or similar non-beneficial
scenarios.
• When using racks correctly, each rack should typically have the
same number of nodes.
• In a scenario that requires a cluster expansion while using
racks, the expansion procedure can be tedious since it typically involves
several node moves and has has to ensure to ensure that racks will be
distributing data correctly and evenly. At times when clusters need immediate
expansion, racks should be the last things to worry about.
------------------ 原始邮件 ------------------
发件人: "Bhuvan Rawal";<bhu1ra...@gmail.com>;
发送时间: 2017年7月24日(星期一) 晚上7:17
收件人: "user"<user@cassandra.apache.org>;
主题: Re: tolerate how many nodes down in the cluster
Hi Peng ,
This really depends on how you have configured your topology. Say if you have
segregated your dc into 3 racks with 10 servers each. With RF of 3 you can
safely assume your data to be available if one rack goes down.
But if different servers amongst the racks fail then i guess you are not
guaranteeing data integrity with RF of 3 in that case you can at max lose 2
servers to be available. Best idea would be to plan failover modes
appropriately and letting cassandra know of the same.
Regards,
Bhuvan
On Mon, Jul 24, 2017 at 3:28 PM, Peng Xiao <2535...@qq.com> wrote:
Hi,
Suppose we have a 30 nodes cluster in one DC with RF=3,
how many nodes can be down?can we tolerate 10 nodes down?
it seems that we are not able to avoid the data distribution 3 replicas in the
10 nodes?,
then we can only tolerate 1 node down even we have 30 nodes?
Could anyone please advise?
Thanks
