How to create Distributed Replicated Volumes from 3 servers with 2 disks?

Question

linux

Firework!
I can't understand how to create "complex" volumes in GlusterFS.
I have 3 servers, each with 2 disks, and I want to make sure that when one of them is turned off, my cluster does not fall apart. As I understood from the documentation, if I do

gluster create volume somevol replica 3 [s1_d1 s2_d1 s3_d1] [s1_d2 s2_d2 s3_d2]

(I deliberately took them in brackets to visually separate them)
then, it turns out that each triple is one replica, and the content is "smeared" over these two replicas? And it turns out that if you turn off one (or even two) servers, the files will remain intact?

Answer 1

Replica = copy. Each triple in your example will contain three copies of the same file (a set of copies). Each recorded file will fall into one of the copy sets (according to the hash of the path to the file, its name and some "salt").
The files will remain intact when the servers are turned off, but access to them may be terminated. By default, in order to maintain access (including for writing), at least 50% of the file copies (two in your case) must be available to the client. That is, without stopping access to files, it will be possible to turn off no more than one server.