American Megatrends ManageTrends 2.7, Руководство пользователя

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StorTrends® 1300 User’s Guide (StorTrends iTX version 2.7) 320
Ethernet snap
Packet format that has its own definition.
+-----------+--------+---------+-------+-------+-------+-----------+--------+-----------
|destination| source | length | AA | AA | 03 | org code | type | data >
+-----------+--------+---------+-------+-------+-------+-----------+--------+-----------
< 3 > < 2 > < 38-1492 >
Failover
Failover is a process by which a PASSIVE system (B) is made as ACTIVE in the event
of a irrecoverable failure of the ACTIVE system (A). During a Failover operation, the
PASSIVE system (B) will rollback to the latest available snapshot – snap group across all
volumes. After a failover the PASSIVE box (B) will become ACTIVE. If volume is of
type SAN, the iSCSI initiator can connect to the volumes in the Consistency group and
start performing I/Os. NAS volumes will be mounted and shares will be made available
after a Failover from the newly ACTIVE system (B).
Failback join
Failback join is a process by which the old ACTIVE system (A) joins with the new
ACTIVE system (B) after a failover. The old ACTIVE system (A) will become
PASSIVE and starts receiving snapshots from the new ACTIVE system (B). In such
scenarios, the most recent matching snap group is identified across old ACTIVE (A) and
new ACTIVE (B) and Snap Assisted Replication starts from that point onwards from the
new ACTIVE (B) to old ACTIVE (A).
Failback
Failback is a process in which the current PASSIVE system (A) regains ACTIVE role
from current ACTIVE system (B). Sometimes the administrator might prefer to recover
the new PASSIVE to ACTIVE after a Failover due to administrative reasons. This
normally happens after a failback join and after all snapshots in the ACTIVE system (B)
are replicated to PASSIVE system (A). After Failback, the system (A) will become
ACTIVE and system (B) will become PASSIVE. Volumes will be exported from system
(A) for normal IO (SAN volumes) or as Shares (NAS volumes). Snap Assisted
Replication will happen from ACTIVE system (A) to PASSIVE system (B).
Failback is an identical reverse operation of Failover and all the steps mentioned in
Failover are done during a Failback.