LUN (VLL) and Volume Shredder User Guide (T5214-96094, November 2011)

Table 22 Estimated Required Time for Quick Formatting

(continued)

Required Time (hours)Capacity of a Drive (GB)

17.5750

23.51000

• Table 22 (page 74) indicates the required time when you execute quick formatting on all the

areas in a parity group. When you execute quick formatting on some volumes in a parity

group, the required time may be less than the time indicated in Table 22 (page 74).

• If an I/O operation is performed from a host, the required time might be five times as long

as or longer than the required time shown in Table 22 (page 74).

• When you execute quick formatting on multiple parity groups, the required time may be longer

than the required time shown in Table 22 (page 74). Formatting 15 parity groups requires

twice as much time, and formatting 30 parity groups requires three times as much time as

shown in Table 22 (page 74).

• The required time shown in Table 22 (page 74) might be as much as four times longer,

depending on the configuration of disk adapter (DKA) pairs.

• When you execute quick formatting at the same time on multiple parity groups that have

different drive capacities, calculate the required time for the parity group that has the largest

capacity.

Host performance might be affected during the execution of quick formatting. Table 23 (page 75)

indicates the estimated performance of a host. However, the values in Table 23 (page 75) might

vary depending on the conditions.

Table 23 Estimated Performance of a Host during Quick Formatting

Performance (%), where 100% Indicates the

Performance when No Quick Formatting is Executed

How to Access

80Random read

20Random write to the unformatted area

60Random write to the formatted area

90Sequential read

90Sequential write

Creating System Disks

System disks are volumes that are used for the storage system. To execute Quick Format, you must

create the system disk in a free space in a parity group. System disks can be created by performing

either the Install CV operation or the Make Volume operation. For detailed information about these

operations, see “Creating VLL Volumes (Install CV Function)” (page 63) and “Re-creating the CVs

After Initializing the VDEV (Make Volume Operation)” (page 67).

Virtual LVI/LUN Operations 75