Replies inline: On 7 February 2014 10:11, Scott Dungan <scott@xxxxxxxxxxxxxxx> wrote: > I am new to Gluster and I am having a hard time grasping how Gluster > functions in distribute mode vs. distribute+replication. I am planning on > having 5 servers, with each server hosting a raid6-backed 36TB brick. For > simplicity, lets just pretend this is a 40TB brick. Here are my questions: > > 1. If I do a distribute configuration only, usable capacity of the Gluster > volume will be 5x40TB or 200TB? Using "40TB" as a round number per brick: distribute (no replicate) would be a single ~200TB GlusterFS volume. > 2. In this configuration, what would clients see if one of the servers were > to fail? Lots of errors. Typically, every fifth file or directory would be missing, and you'd see lots of question marks in your "ls -l" output. > 3. When the server comes back up, what steps would need to be taken to make > the Gluster volume consistent again? In a distribute-only setup, there's no redundancy. So there's no "consistency" so to speak. When the missing volume came online, the files it holds would be available again. > 4. if I do a distributed replicated (2) volume, will my usable capacity > become 160TB or 100TB, or perhaps something else entirely? 5 servers is an uneven amount of bricks. You'd end up with 120TB, but 40TB of that wouldn't be replicated. A 6th brick would solve that problem, and you'd have ~120TB in full distribute+replicate(2). > 5. In this configuration, one server may be removed for maintenance and the > file system stays consistent? Theoretically yes. I try to keep my replicated brick downtime to a minimum though. Similar to the ideas behind a RAID mirror, I don't like running in production on only one copy of something for too long. -Dan _______________________________________________ Gluster-users mailing list Gluster-users@xxxxxxxxxxx http://supercolony.gluster.org/mailman/listinfo/gluster-users
