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11.1 ETERNUS CS800 Replication Overview
To schedule replication for a share or partition, use the Configuration >
Scheduler page (see
290). To limit the amount of network bandwidth used for replication, enable a
constant throttle (see
replication throttling (see
Understanding Data Replication
During data replication, data is sent from one system (the source) to another system, usually
in another location (the target). For example, you might replicate data from a branch office
(the source) to a central office (the target).
Sources send replicated data, and targets receive replicated data. A target system can
receive data from up to ten sources. A source system can send data to up to two targets.
Finally, one system can act as both a source and a target.
Replication works only with deduplicated data, and data is compressed before it is replicated.
Because of this, the amount of data transmitted between systems during replication is
greatly reduced compared to the original amount of data stored. In addition, a data block is
transmitted only if the target does not already have a copy of the block. Finally, data can
optionally be encrypted before it is transmitted.
The ETERNUS CS800 can perform the following types of replication:
"Replication" on page 364
l
"Directory/File or Cartridge Based Replication" on page 365
l
"OST Optimized Duplication" on page 366
l
"Multiple Target Replication" on page 366
l
Replication
Replication occurs when replication is enabled for a deduplicated NAS share or VTL partition
and a replication schedule is configured (or manual replication is performed on a regular
basis). For replication to occur, the source system must be configured to point to the target
system. Similarly, the target system must be configured to accept data from the source
system.
To optimize the replication process, deduplicated data is continuously sent in the background
from the source system to the target system. However, a snapshot that preserves the file
structure of your data is sent to the target system only when a scheduled or manual
replication job occurs. A snapshot contains all of the information that is necessary to recreate
a share or partition just as it was at the point in time when the snapshot was created.
364
"Scheduling a Share or Partition for Replication" on page
"Enabling System Throttling" on page
"Scheduling Replication Throttling" on page
276), or schedule
291).
ETERNUS CS800
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