Example 4: 500 Gb Virtual Cartridge Replication Over A 10 Mbit/Sec Link - HP StorageWorks 12000 - Virtual Library System EVA Gateway Manual

Calculating data to replicate:
• 500 GB daily backup to replicate within a 12–hour fixed window (between 20:00 and 08:00).
• 1% daily change rate = 3.3 GB compressed
• Overhead (manifest, imperfect match, etc.) is 1.5% = 7.5 GB
• Total data to transmit is 10.8 GB
Result:
• Initial 500 GB backup complete in 2.75 hours.
• Replication time for 10.8 GB is 18.1 hours over this link at 100% bandwidth utilization
does not meet the service level agreement.
In this example, start off with the an 2 Mbit SDSL link. You soon realize that the 10.8 GB of data to
replicate even using 100% of the available bandwidth is 18.1 hours which is outside most users'
fixed window of available time. It would take 4 x 18.1 hours using 25% throttling of the 2 Mb/sec
link. Clearly a link speed upgrade is required to meet either of your criteria.
Upgrading to a 10 Mbit/sec link resolves the problem.
The replication time now within a fixed window is 18.1/5 = 3.62 hours.
The replication time now with shared bandwidth mode at 20% = 18.1 hours (within the required 24
hours required).
Figure 35 Example 4: 500 GB Virtual Cartridge Replication over a 10 Mbit/sec Link
.
Calculating data to replicate:
• The same data calculations as the example in
• The total data to transmit is 10.8 GB.
Results:
• Initial 500 GB backup complete in 2.75 hours.
• Replication time for 10.8 GB is 18.1 hours over this link at 25% bandwidth utilization.
Finally, look at a many-to-one example which is a combination of the above scenarios.
Figure 34.
HP StorageWorks VLS and D2D Solutions Guide
but this
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