HP XP7 Storage - Manual (Page 5)

You can configure Volume Shredder to overwrite data from three to eight times, and each time the
system overwrites the data you can configure the dummy data to be any hexadecimal number
from 0 to FFFF.
After the system finishes overwriting data, you can view the results in the user interface or, if
configured, you can open the compressed results files.
We recommend that you execute the shredding function at times of day when the host I/O load
is lowest. If the number of LDEVs to be shredded is large, shredding operations might affect host
I/O operations. Use the following formula to determine the standard required time for a shredding
operation.
(time required for shredding) = (time required for one dummy data write (standard required time)) x (number of
times dummy data is written (n))
Shredding times
The following tables show the standard required times for shredding without host I/O, listed by
drive type. The same standard times also apply to shredding encrypted drives. The standard
required time in each table assumes the use of OPEN-V volumes.
For DKxxx-JxxxSS/KxxxSS/HxxxSS disk drives:
Standard required time* RAID level Rotation per minute
85 minutes 2D+2D RAID 1 15 Krpm
65 minutes 3D+1P RAID 5
30 minutes 7D+1P
Shredding times 5