Global cache services (LMSn)

Global cache services (LMSn) are processes that, when spawned by Oracle,
copy blocks directly from the holding instance’s buffer cache and send a
read-consistent copy of the block to the foreground process on the requesting
instance.

LMS also performs a rollback on any uncommitted transactions
for any blocks that are being requested for consistent read by the remote
instance.The number of LMS processes running is driven by the parameter

GCS_SERVER_PROCESSES.

Oracle supports up to 36 LMS processes (0–9 and a–z).


If the parameter is not defined, Oracle will start two LMS processes,which is the default value of GCS_SERVER_PROCESSES.