[Gluster-users] to RAID or not?

[Russell Purinton]

Sorry, example of 5 servers should read

> 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 1 C & D


Adding each server should be as simple as using the brick-replace command to move bricks C and D from server1 onto bricks C and D of the new server.

Then you can add-brick to create 2 new brick replicas from new server A and B to server1 C and D.


> On Jul 4, 2016, at 1:54 PM, Russell Purinton <russell.purinton at gmail.com> wrote:
> 
> 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 ?
>