Hitachi Storage Navigator Modular 2 User Guide

							Managing RAID Groups8–13
Hitachi Storage Navigator Modular 2 User’s Guide
Executing a RAID group spin-up or spin-down
Spinning down drives saves energy by spinning down the drive’s motor 
when the drive is idle. Navigator 2 lets you configure the drives in RAID 
groups to spin down automatically when idle. This feature is useful for 
organizations having a hard time meeting the demand for power in their 
data centers, either because power companies cannot generate sufficient 
power or the required infrastructure does not exist. The amount of power 
that spin down saves is proportional to the amount of time a drive spends 
being idle. The drive’s motor does not run when the drive is idle; the only 
power needed in idle mode is the power required by the electronics.
Alternatively, Navigator 2 lets you configure drives in RAID groups to spin-
up.
To spin up or spin down the disks of a selected RAID group
1. In the Arrays window, select the storage system whose RAID group you 
want to spin up.
2. In the center pane, click Power Saving > RG Power Saving. The RG 
Power Saving window appears (see Figure 8-8).
Figure 8-8:  RG Power Saving Window
3. Select the RAID group that you want to spin up and click Execute Spin 
Up to spin up the disks or Execute Spin Down to spin down the disks 
in the selected RAID group. A confirmation window appears. 
						

							8–14Managing RAID Groups
Hitachi Storage Navigator Modular 2 User’s Guide
4. Review the setting in the window and click Confirm to perform the spin 
up or spin down (or click Cancel to cancel the operation).
5. When the next window appears, click Close.
Changing RAID group expansion priority
Using the Change Priority button, you can change expansion priority for a 
selected RAID group between host access and RAID group access.
To change the RAID group expansion priority
1. In the left column of the RAID Groups tab of the Logical Units window, 
click the checkbox of the RAID group whose expansion priority you want 
to change.
2. Click Change Priority. The Change Priority of RAID Group Expansion 
window appears (see Figure 8-9).
Figure 8-9:  Change Priority of RAID Group Expansion Window
3. Click the desired priority, Host Access or RAID Group Expansion.
4. Click OK. A warning message appears.
5. In the displayed message box, read the confirmation and warnings, then 
click the check box to the left of the text to agree.
6. Click Confirm to change the priority (or click Cancel to not change the 
priority.)
7. When a message states that the operation was successful, click Close 
to close the window and return to the RAID Groups tab. 
						

							Managing RAID Groups8–15
Hitachi Storage Navigator Modular 2 User’s Guide
Filtering RAID groups
The RAID Groups tab provides a Filter button you can use to filter out RAID 
groups that do not meet certain criteria. This feature is particularly useful if 
you have a large number of RAID groups and only want to see a subset of 
them.
To filter RAID groups
1. In the RAID Groups tab in the Logical Units window, click the Filter 
button. The Array List Filter window appears (see Figure 8-10).
Figure 8-10:  Example of Array List Filter
2. In the drop-down list, select whether you want to view All or Any RAID 
groups that meet the filtering criteria.
3. Use the Attribute, center, and Value drop-down lists to define the first 
criteria.
4. To define additional criteria, click the plus sign. When the next row 
appears, define a second set of criteria. You can also click the minus sign 
at the end of a row to delete that set of criteria from the filter.
5. When you finish defining criteria, click OK. Now only the RAID groups 
that meet your filtering criteria appear in the RAID Groups tab.
6. To remove all filtering criteria and redisplay all RAID groups in the RAID 
Groups tab, click Filter Off.
NOTE:The more criteria you define, the narrower the filtering becomes. 
						

							8–16Managing RAID Groups
Hitachi Storage Navigator Modular 2 User’s Guide
Deleting RAID groups
If you no longer need a RAID group, you can delete it from the RAID Groups 
tab. When you delete a RAID group, all logical units associated with the 
RAID group are also deleted.
To delete a RAID group
1. In the left column of the RAID Groups tab of the Logical Units window, 
click the checkbox of the RAID group you want to delete.
2. Click Delete RG. A confirmation window appears. 
3. In the confirmation window, click the checkbox to agree that you have 
read the warning message, and then click Confirm to delete the RAID 
group (or click Cancel to retain it).
4. Click Close to close the window and return to the RAID Groups tab. 
						

							Managing Logical Units9–1
Hitachi Storage Navigator Modular 2 User’s Guide
9
Managing Logical Units
This chapter describes how to perform logical unit tasks on 
Hitachi AMS 2000 Family storage systems using Navigator 2
The topics covered in this chapter are:
ˆOverview
ˆDisplaying the Logical Units window
ˆCreating a logical unit
ˆChanging LUN capacity
ˆDisplaying unified logical unit properties
ˆFormatting logical units
ˆFiltering logical units
ˆDeleting logical units 
						

							9–2Managing Logical Units
Hitachi Storage Navigator Modular 2 User’s Guide
Overview
Logical units are user-designated partitions of the free storage space in a 
storage system and are used by a host to manage the data in the storage 
space they define. A logical unit can include all of the free storage space on 
a storage system or only part of it. 
For example, you can create a logical unit for the free space on each drive, 
or divide the free space on a drive into parts and create a logical unit for 
each part. The parts can be any size you want. You could also create a 
logical unit that includes part of the free space on each of the drives.
The number of logical units you can create depend on your system. Refer to 
the users guides for your systems specifications.
Identifying logical units
Each logical unit is assigned a number to identify it. The numbers can be 
from 0 to 1023 and are called Logical Unit Numbers, or LUNs. Since the 
LUNs are the usual way to refer to the logical units, the acronym LUN is 
often used instead of logical unit.
 Types of logical units
There are several types of LUNs that can be created and used on the storage 
system.
• Standard logical units (LUNs) are just designated partitions of storage 
space. LUNs are also called volumes.
• Differential Management Logical Units (DMLUs). DMLUs are logical units 
that consistently maintain the differences between them.
• SnapShot Logical Units are virtual volumes and are specified as the 
secondary volume of a SnapShot pair when you create a pair. See 
Create SnapShot Logical Unit for more information.
Understanding preconfigured logical units
AMS 2000 Family storage systems are set up at the factory with one or more 
logical units, depending on the model. This helps users by making the 
storage systems easier and faster to configure. The factory configurations 
are described below, by model.
AMS 2000 Family storage systems are set up at the factory with one pre-
configured LUN. Table 9-1 lists the parameters of that LUN. If desired, you 
can create additional logical units.
Table 9-1:  Preconfigured LUN on AMS 2000 Storage Systems
No. 
CtlrsNo. 
LUNsLUN Nos.LUN 
TypeSizePort Purpose/Notes
2 1 LUN 0 LUN 50 GB 0A • Normal use. 
• Can be allocated to a host. May 
be spread across multiple drives. 
						

							Managing Logical Units9–3
Hitachi Storage Navigator Modular 2 User’s Guide
Displaying the Logical Units window
All logical unit activities described in this chapter are performed from the 
Logical Units window. 
To display the Logical Units window
1. In the Arrays window, click the name of a storage system under the 
Array Name column in the Arrays window
2. In the center pane, click Groups > Logical Units. The Logical Units 
window appears.
3. In the Logical Units window, click the RAID Groups tab. Figure 9-1 shows 
an example of RAID groups in the RAID Groups tab.
Table 9-2 summarizes the logical unit activities you can perform.
Figure 9-1:  Example of RAID Groups Tab
Table 9-2:  Logical Unit Tasks
TaskSee Page
Create logical units 9-4
Change the capacity of a logical unit 9-6
Change LUN capacity 9-6
Display detailed properties about a logical unit 9-11
Format logical units 9-11
Filter logical units shown in the Logical Units tab 9-12
Delete logical units 9-13 
						

							9–4Managing Logical Units
Hitachi Storage Navigator Modular 2 User’s Guide
Creating a logical unit
To create a logical unit
1. In the Logical Units tab, click Create LU. The Create Logical Unit window 
appears.
2. Click the Basic tab.
Figure 9-2:  Create Logical Unit Window (Basic Tab)
3. Complete the settings in the tab (see Table 9-3 on page 9-5).
4. To set advanced options, click the Advanced tab and complete the 
settings (see Figure 9-3 on page 9-5). If you do not need advanced 
settings, or if you created a logical unit in the DP pool, skip to the next 
step. 
						

							Managing Logical Units9–5
Hitachi Storage Navigator Modular 2 User’s Guide
Figure 9-3:  Create Logical Unit Window (Advanced Tab)
5. Click OK. 
6. When the results window appears, click Close.
Table 9-3:  Create Logical Unit Window (Basic Tab)
FieldDescription
RAID Group Select a RAID group from the drop-down list.
LUN From 0 to the maximum supported by the storage system.
Capacity • For RAID groups: from 1MB/GB/TB/Block to max 
(depending on the amount of free space) Select ALL to 
assign the maximum free space in the selected RAID 
group. Select RG ALL to assign all free space for the 
selected RAID group.
• For a DP pool: from 32MB to the maximum supported by 
the storage system.  
						

							9–6Managing Logical Units
Hitachi Storage Navigator Modular 2 User’s Guide
Changing LUN capacity
After you create a logical unit, you can e x p a n d  ( g r o w )  o r  r e d u c e  ( s h r i n k )  i t s  
size. You can also unify (concatenate) or separate logical units to increase 
capacity. You perform these tasks from the Change Logical Unit Capacity 
window.
Guidelines when expanding logical units
Observe the following guidelines when expanding or reducing logical units.
Expanding logical units
You cannot expand a logical unit under the following circumstances:
• When the logical unit you want to expand is being formatted.
• For a unified logical unit configured using logical units of two or more 
RAID groups. 
• During a drive restoration is in progress on the affected logical unit. 
Execute after completing the drive restoration.
• On the following types of logical unit:
•  Logical units set as a pair of ShadowImage in-system replication
•  Logical units set as a pair of Copy-on-write SnapShot
•  Logical units set as a pair of TrueCopy remote replication
•  Logical units set as a pair of TrueCopy Extended Distance
•  Logical units or reserve logical units for Modular Volume Migration
•  Logical units in which Cache Residency Manager is set
•  Logical units being formatted
Table 9-4:  Create Logical Unit Window (Advanced Tab)
FieldDescription
Stripe Size Size to write separated data to drive.
Partition Settings Specify the cache partition and pair cache partition settings.
Format the Logical 
UnitCheck to format the created logical unit. For a logical unit in the 
RAID group, the format is performed on the six logical units per 
controller at the same time. If you specify more logical units 
than the controller allows, the units enter a queue and wait until 
the system is available to process them. They are released from 
the queue for processing when the logical units that entered the 
optimization cycle before the maximum amount reached has 
completed processing. The waiting logical units execute 
automatically when they can be accepted
Select  free  space Amount of free space you want to create for the logical unit and 
set manually or set automatically. To set manually, check a 
selection in the Free Space table. In the Used LUN to create 
Logical Unit field, specify the first LUN to be used to create the 
LU. Note that in some storage systems, you cannot set 
automatically or manually, and can only select free space.