Vls Sizing Example 3; Summary Of The Calculations Involved In The Sizing Examples - HP StorageWorks 12000 - Virtual Library System EVA Gateway Manual

Figure 81 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 1100bit/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 dedu-
plication technology would have taken 205 hours on DWDM 4Gb Fibre Channel at significantly
higher cost. While some may say 1 GB/sec is not low bandwidth, everything is relative to the
task at hand.
Table 27 Summary of the Calculations Involved in the Sizing Examples
Data types (3 Full size in GB
DB:1 FS) &
backup type
Database (Full)
15000
1% change
File data (Full) 5000
Replicated Time avail-
data (com- able to replic-
pressed) in ation/time to
GB replicate
198
24 hours
297
HP StorageWorks VLS and D2D Solutions Guide
Link speed Combined
available or link speed
required in
Mbit/sec
83 at 40% util-
ization 20 Mbits/sec
at 40% utiliza-
125 at 40%
tion
utilization
185