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Required Link - 400Mbit/sec link made available
Typical replication time 12.8 hours
Now consider a larger backup requirement with a full database backup of 50 TB and an
incremental of 10% of 16.6 TB of file system data. Notice how as the amount of data backed
up scales the number of nodes scales, and as the number of nodes scales more processing
power is made available to both backup, deduplication, and replication. Here in this 2–node
system both nodes work to ensure the replication link is saturated at all times. In this example
the Sizer calculations show around 659 GB of data needs to replicate. There is a dedicated
400 Mbit/sec link between sites. The calculations show that this replication can complete
within 12.8 hours (even allowing four hours for the first set of deduplication replication
instructions to be generated, so it is easy to achieve the requirement of backup and replication
within 24 hours).
3.
Sizing Scenario: 266 TB of database and file-system replication.
Figure 54 VLS Sizing Example 3
Database Full Backup size 200TB – 1% change rate
File System Full backup Size 66.6 TB – This example replicates one of the incremental
backups, size of 10%
Initial Replication Window 24 hours
Required Link 1 100bit/sec + some margin for catch-up
Consider 1 Gb/sec link and relax replication window to 26 hours
The final example shows the trade-off and the sheer capabilities of this technology. This
simulates a 266 TB environment being replicated (200 TB database, 66.6 TB file system) with
an initially stated 24 hour replication window (allowing four hours until the first replication
starts). When you run the Sizer calculations in order to replicate this volume of data within
24 hours, it really needs a1200 Mbits/sec link (or 2 x 600 Mbits because few telcos deliver
greater than a 1Gb/sec link). Again note how, because of the volume of data, the number
of nodes has increased and the replication ability has also scaled appropriately. You now
have a choice to either invest in the 2 x 600 Mbit/sec links or compromise on the time to data
off-site. If you are willing to accept data replicated within 26.2 hours, you can save
considerable cost in requiring only a 1 Gb/sec link.
This example replicated the equivalent of 266 TB in just over 26 hours, a task that without
deduplication technology would have taken 205 hours on DWDM 4Gb Fibre Channel at
1 18
Replication
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