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They mentioned that their new config has a delayed replica. Can anyone comment on how useful this actually is? I do snapshots + binlogs so I can do a point-in-
by gatehouse 12y ago
They mentioned that their new config has a delayed replica. Can anyone comment on how useful this actually is?
I do snapshots + binlogs so I can do a point-in-time recovery to any time in the last month. So obviously a delayed replica would be a faster way to recover from human error at the MySQL prompt. But it would still require human intervention which is slow and can't really be automated. On the other hand, presumably a process already exists to bring a replica up from scratch, and that could be done and paused at a certain point. So it seems like a lot of extra effort and hardware for a really narrow and constrained benefit.
Anyone running a delayed replica -- is this wrong? Has it been used ever? often? Worth it?
- samlambert 12y agoIt is certainly helpful for grabbing bits of data that you want quickly, it is also another line of defense for DR. If we make a change and want to quickly compare against an older version of the data delayed slaves are super handy. We can also restore to any point in time with binlogs.
- morgo 12y agoDelayed replicas is a MySQL 5.6 feature (and can be emulated in previous versions). You are correct in that the main use-case is fast recovery from human error. But as a DBA, I can tell you that accidents like this cover 90% of disasters :)
- sjwright 12y agoWe use a delayed replica for our off-site backups. It's a little bit of safety, plus it comes in handy for sanity checking previous state after making big global changes.