Upgrade to shadow device


Recently Aerospike introduce shadow device:


But from documentation it is not clear how to migrate to this setup from previous bcache setup. Should we just use the same EBS from bcache setup as shadow device and Aerospike will find data on it or do something else to move data?

Other question is that I assume at start time Aerospike always copy data from shadow device to primary, is it true?


Yes, haven’t created such a document yet. I suspect it would be something along the lines of:

  1. Know that this procedure hasn’t been verified.
  2. For each node:
  3. Stop Aerospike
  4. dd if=/dev/BCACHE_DEVICE of=/dev/EBS_DEVICE
  5. Remove bcache configuration
  6. Zeroize local ssd: dd if /dev/zero of /dev/LOCAL_SSD
  7. Reconfigure Aerospike to use device /dev/LOCAL_SSD /dev/EBS_DEVICE
  8. Start Aerospike and local device will be synced with shadow device.

It only copies data from the shadow device if the local device doesn’t contain an Aerospike header. Otherwise it will assume the disks are in sync.