by young » Sun Nov 11, 2012 11:29 pm
Let’s say the power supply on a node dies and I replace it. When the node starts up, does it have to get data from the other nodes or does it read from disk?
You can actually choose. Depending on the reason for a node crash, you may find that one option or the other is better. For instance, if the problem was a bad disk, you may no longer have the data and will need to get a copy from the rest of the cluster. If the problem was a bad power supply, the data is still on disk and it is faster to read the data from disk than to transfer it from the other nodes.
If a node has been offline for a long time (more than a few hours), it is recommended not to read from disk. In this case, you should wipe the disk (using dd) before restarting the Aerospike server on the node.