HP B6960-96035 - Manual (Page 324)

Why use the HP StorageWorks DLT 4115w Library?
• The HP StorageWorks DLT 4115w Library has a single DLT4000 drive
with 15 slots. It has a total compressed storage capacity of 600 GB and
a maximum sustained data transfer rate of 3 MB/s, or 10.5 GB/h, with
data compression. This is the transfer rate assumed for the remainder of
this section. Currently, the total amount of data to be backed up at ABC
Pretoria to the HP StorageWorks DLT 4115w Library as a full backup,
whether this is a single full backup, or the staggering approach is used,
is about 22 GB. Assuming that the size of an incremental backup is
approximately 5% of that of a full backup, a backup generation,
representing a full backup and all incremental backups based on this full
backup, requires (22+22*5%*5) GB, or 27.5 GB, of library space. In five
years time, this figure is projected to increase to about 68.75 GB. ABC’s
backup policy requires that three backup generations of data be kept.
Therefore, 68.75*3 GB, or 206.25 GB, of library space will be required
for storage. The HP StorageWorks DLT 4115w Library’s 600 GB storage
capacity therefore suffices.
HP StorageWorks DAT24 autoloaders are used to back up the Microsoft
Exchange Server and Microsoft SQL Server at ABC Cape Town as well as
each of the 7 Cell Managers in the 3 MoM environments.
Why use the HP StorageWorks DAT24 Autoloader?
• The HP StorageWorks DAT24 autoloader has 6 24-GB data cartridges.
It has a total compressed storage capacity of 144 GB and a maximum
sustained data transfer rate of 2 MB/s, or 7 GB/h, with data compression.
This is the transfer rate assumed for the remainder of this section. Currently,
the total amount of data to be backed up to the HP StorageWorks DAT24
autoloader connected to the aforementioned Microsoft Exchange Server
at ABC Cape Town is 15 GB. Assuming that the size of an incremental
backup is approximately 5% of that of a full backup, a backup generation,
representing a full backup and all incremental backups based on this full
backup, requires (15+15*5%*5) GB, or 18.75 GB, of space. In five years
time, this figure is projected to increase to about 47 GB. ABC’s backup
policy requires that two backup generations of data be kept. Therefore,
47*2 GB, or 94 GB, of library space will be required for storage. The HP
StorageWorks DAT24 autoloader’s 144 GB storage capacity therefore
suffices.
How long does a full backup last?
The SAP database servers in the three cells at ABC Cape Town contain about 74
GB of data to be backed up to an HP StorageWorks DLT 4228w Library. This
Backup scenarios 324