Bug #39307
closedEC pools with m=1 are created with an unsafe min_size by default
0%
Description
Creating an EC pool with m=1 on 14.2.0 defaults to a min_size of k, e.g. min_size of 2 for a 2+1 pool.
Older versions defaulted to a min_size of 3.
I don't think we should go for a default that favors availability over durability ever. It should be a conscious choice by the user to run a cluster that accepts writes with no redundancy.
Updated by Greg Farnum about 5 years ago
Hmm, is this a default EC mode or just something we let users set?
The change was deliberate in PR https://github.com/ceph/ceph/pull/26894 following discussion on https://github.com/ceph/ceph/pull/8008 and I'm not sure how much we want to prevent users shooting themselves in the foot.
Updated by Sage Weil about 5 years ago
- Status changed from New to Won't Fix
This was a deliberate choice. https://github.com/ceph/ceph/pull/26894 made teh change, based on a discussion on another PR, https://github.com/ceph/ceph/pull/8008
I think the udnerlying problem is that 2+1 is just a bad choice.. either you tolerate no failures at all or durability is also weak. I suggest we change the default EC profile to 2+2 instead?
Updated by Sage Weil about 5 years ago
Updated by Paul Emmerich about 5 years ago
Yeah, changing the default ec profile also works