Even though this has nothing to do with persistence (though I can see how you'd think it does from the OP title), I just want to give you a different perspective (again, this doesn't really have anything to do with what Antirez is actually saying)"
What's more reliable? Data persisted to disk on a single server in a RAID 1 array, or data stored in memory of 10 machines which are completely isolated from each other? What about 100 machines?
It's wrong to think of disks as reliable/persistent and memory as not. You should think of both as stores where neither is 100% reliable. Memory is far less reliable than disk, much in the same way that a single disk is less reliable than RAID-6. However, just like you can make disks more reliable by replicating across other disks (and then even more reliable by replicating across multiple servers...in multiple locations), so too can you achieve reliability with memory.
EDIT (clarify what they are talking about):
They aren't talking about persistence, though I can see why you think that from the OP title. They are talking about loading the data set into virtual memory when it doesn't fit into memory.
This has nothing to do with persistence. Antirez isn't saying he doesn't trust Redis' persistence implementation. He's specifically talking about how the Redis VM handles more data than available memory.
He's saying: always have enough memory for all your data.
What's more reliable? Data persisted to disk on a single server in a RAID 1 array, or data stored in memory of 10 machines which are completely isolated from each other? What about 100 machines?
It's wrong to think of disks as reliable/persistent and memory as not. You should think of both as stores where neither is 100% reliable. Memory is far less reliable than disk, much in the same way that a single disk is less reliable than RAID-6. However, just like you can make disks more reliable by replicating across other disks (and then even more reliable by replicating across multiple servers...in multiple locations), so too can you achieve reliability with memory.
EDIT (clarify what they are talking about):
They aren't talking about persistence, though I can see why you think that from the OP title. They are talking about loading the data set into virtual memory when it doesn't fit into memory.
This has nothing to do with persistence. Antirez isn't saying he doesn't trust Redis' persistence implementation. He's specifically talking about how the Redis VM handles more data than available memory.
He's saying: always have enough memory for all your data.