Host-Based Mirroring
ƒ More impact on server
processor
ƒ Impact on application
performance depends upon:
Data ƒ File system and software used
ACK
ƒ Speed and bandwidth of
connections
SAN SAN
ƒ Whether servers and arrays are
local or remote
Here the host writes to the primary, and to the secondary, the primary
acknowledges, the secondary acknowledges.
If it’s synchronous it waits for both acknowledgements.
If it’s asynchronous the application will move on after the primary
acknowledges, but it still waits for the secondary before clearing out its
buffers.
Obviously if we use host based replication this will now work with any storage
vendor because as long as we can see the logical units we can mirror
between them.
How much impact on the application server depends on the file system, the
software, the infrastructure and the latency.