Fujitsu ETERNUS CS800, User Manual

Page: 365 / 604

CAUTION!
A saved snapshot is necessary to recover your data at a later time. For this reason, it is
not enough to simply enable replication for a share or partition. You must also configure
a replication schedule (recommended) or perform manual replication on a regular basis
to send snapshots of the share or partition to the target system.
If the source system ever becomes unavailable, you can recover the share or partition on the
target system using a saved snapshot. After you recover a share or partition, it is recreated
on the target system and is available for use. Once the source system becomes available
again, you can perform a failback operation to restore the share or partition to its original
location.
Directory/File or Cartridge Based Replication
Like replication, Directory/File or Cartridge Based Replication sends data from a NAS share
or VTL partition to another system where it can be accessed. However, Directory/File or
Cartridge Based Replication differs in a number of important ways:
l
Both replication and Directory/File or Cartridge Based Replication must be enabled for
the share or partition.
l
A unique Sync ID is used to associate the replicated share or partition on the source
system with the share or partition that will receive the replicated data on the target
system.
l
You do not need to schedule or manually perform Directory/File or Cartridge Based
Replication through the remote management console. Instead, replication is triggered
when a file is closed or a period of time after it is modified (NAS shares), or when a tape
cartridge is unmounted (VTL partitions).
For CIFS shares, a file is replicated immediately after it is closed. For NFS
shares, a file is replicated after it has been idle (not accessed) for several
minutes..
To optimize the replication process, deduplicated data is continuously sent in
the background from the source system to the target system. Any remaining
data is sent (along with metadata) at the time a file is closed or a tape
cartridge is unmounted.
l
After files or cartridges are replicated using Directory/File or Cartridge Based
Replication, they are automatically recovered on the target system and are immediately
available for use. There is no need to first recover the share or partition to access its
data.
l
Deletions are automatically propagated from the source system to the target system in
order to free up pace on the target. In addition, you can manually initiate a
ETERNUS CS800 365
11 Replication