[Gluster-users] to RAID or not?

[Russell Purinton]

The fault tolerance is provided by Gluster replica translator.

RAID0 to me is preferable to JBOD because you get 3x read performance and 3x write performance.   If performance is not a concern, or if you only have 1GbE, then it may not matter, and you could just do JBOD with a ton of bricks.

The same method scales to how ever many servers you need… imagine them in a ring…

server1 A & B   replica to server 2 C & D
server2 A & B   replica to server 3 C & D
server3 A & B   replica to server 1 C & D

Adding a 4th server?  No problem… you can move the reconfigure the bricks to do
server1 A & B   replica to server 2 C & D
server2 A & B   replica to server 3 C & D
server3 A & B   replica to server 4 C & D
server4 A & B   replica to server 1 C & D

or 5 servers
server1 A & B   replica to server 2 C & D
server2 A & B   replica to server 3 C & D
server3 A & B   replica to server 4 C & D
server4 A & B   replica to server 5 C & D
server5 A & B   replica to server 6 C & D

I guess my recommendation is not the best for redundancy and data protection… because I’m concerned with performance, and space, as long as I have 2 copies of the data on different servers then I’m happy.  

If you care more about performance than space, and want extra data redundancy (more than 2 copies), then use RAID 10 on the nodes, and use gluster replica.  This means you have every byte of data on 4 disks.

If you care more about space than performance and want extra redundancy use RAID 6, and gluster replica.

I always recommend gluster replica, because several times I have lost entire servers… and its nice to have the data on more than server.

> On Jul 4, 2016, at 1:46 PM, Gandalf Corvotempesta <gandalf.corvotempesta at gmail.com> wrote:
> 
> 2016-07-04 19:44 GMT+02:00 Gandalf Corvotempesta
> <gandalf.corvotempesta at gmail.com>:
>> So, any disk failure would me at least 6TB to be recovered via
>> network. This mean an high network utilization and as long gluster
>> doesn't have a dedicated network for replica,
>> this can slow down client access.
> 
> Additionally, using a RAID-0 doesn't give any fault tollerance.
> My question was for archieving the bast redundancy and data proction
> available. If I have to use RAID-0 that doesn't protect data, why not
> removing raid at all ?