HP XP7 Storage - Manual (Page 9)

Blocking volumes in a parity group
You must have the Storage Administrator (Provisioning) role to perform this task.
To block volumes in a parity group:
1. Display the Parity Groups tab by choosing one of the following steps, depending on the
location of the parity group:
•
In the Storage Systems tree, select Parity Groups.
•
In the Storage Systems tree, select Parity Groups and then Internal or External.
2. Confirm the current status of the volume by viewing the Status column of the table.
•
If the volume is already blocked, Blocked will appear in the status column.
•
If the volume is not blocked, a status other than Blocked will appear in the status column.
3. Select the parity group you want to block and choose one of the following steps:
•
Click More Actions, then select Block LDEVs. The Block LDEVs window will display.
•
Click Actions, select Logical Device, then select Block LDEVs. The Block LDEVs window
will display.
4. Note the settings in the Block LDEVs window and either enter a unique task name or accept
the default name and click Apply.
If Go to tasks window for status is selected, the Tasks window will open.
Related topics
•
The Block LDEVs section in the HP XP7 Provisioning for Open Systems User Guide.
•
The Top window when selecting Logical Device section in the HP XP7 Provisioning for Open
Systems User Guide.
•
The Top window when selecting Internal or External of Parity Group section in the HP XP7
Provisioning for Open Systems User Guide.
Calculating the number of overwrite passes for flash drives
Because of the way space is allocated in flash drives, the dummy data that is used to overwrite
the volume must exceed the capacity of the target volume. Therefore, before you shred a volume
on flash drives, you need to calculate the number of times the system must overwrite the volume
with dummy data.
You must have the Storage Administrator (Provisioning) role to perform this task.
1.
Select an LDEV in Logical Device and write down its capacity and the amount of data in the
RAID configuration (found on the LDEVs tab).
Examples of amounts of data in a RAID configuration:
n of RAID5(nxD + 1P)
n of RAID6(nxD + 2P)
2. Use the following formula to calculate the number of times to overwrite the data (N):
N = (User-capacity-for-Data x 2) / Capacity-of-target-volume
When the capacity of the flash drive is 400 GB, 400 GB x n
Example: The capacity of the flash drive is 400 GB, the RAID configuration is 3D+1P, and
the LDEV capacity is 440 GB.
[(400 x 3) x 2 ] / 440 = 5.45 = six times
Round up the value (5.45) to the nearest whole number. You need to overwrite the data six
times.
Blocking volumes in a parity group 9