Mirror Cascades
In a cascade, one mirror synchronizes to the source volume, and
each successive mirror uses a previous mirror as its source. Mirror
cascades are useful for propagating data over a distance, then
re-propagating the data locally instead of transferring the same
data remotely again for each copy of the mirror. In the example
below, the <
character indicates a mirror's
source:
/ < mirror1 < mirror2 < mirror3
A mirror cascade makes more efficient use of your cluster's network bandwidth, but synchronization can be slower to propagate through the chain. For cases where synchronization of mirrors is a higher priority than network bandwidth optimization, make each mirror read directly from the source volume:
mirror1 > < mirror2
/
mirror3 > < mirror4
You can create or break a mirror cascade made from existing mirror volumes by changing the source volume of each mirror in the Volume Properties dialog of the MapR Control System.