HP StorageWorks XP128 User manual

HP StorageWorks
Cache LUN XP user guide
for the XP128/XP1024
Part number: T1616-96001
First edition: July 2005

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Cache LUN XP user guide for the XP128/XP1024

Cache LUN XP user guide for the XP128/XP1024 3
About this guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Intended audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Prerequisites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Related documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Document conventions and symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
HP technical support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
HP-authorized reseller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Helpful web sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1 Cache LUN XP for the XP128/XP1024 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Supported volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Cache LUN XP tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Supported emulation types and other parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Supported emulation types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Modified volume types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Unit of cache area allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Number of cache areas allowed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Restrictions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Cache LUN XP modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Priority mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Priority mode details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
General cache capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Bind mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Bind mode details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Bind mode and RAID groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Pre-staging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Starting Cache LUN XP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Cache LUN pane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Prestaging check box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
LDEV tree. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
LDEV table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Cache LUN pie chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Cache settings section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Setting (creating) a cache extent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Releasing (removing) a cache extent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Changing an extent’s mode and pre-staging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Partial Cache Residence (PCR) operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Overview of the PCR function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
PCR operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
PCR pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Viewing the current PCR settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Setting the PCR cache for management information (i-node) and log information . . . . . . . . . . . . . . . . . 19
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figures
1 Cache LUN XP operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Cache LUN pane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3 Multi Set pane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4 Multi Release pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5 PCR cache area (cache extent) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6 PCR Pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7 PCR pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Contents

4
Tables
1 Document conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3 Cache LUN XP icons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Cache LUN XP user guide for the XP128/XP1024 5
About this guide
This guide provides information about:
•”Supported volumes” on page 9
•”Cache LUN XP tasks” on page 9
•”Supported emulation types and other parameters” on page 9
•”Restrictions” on page 10
•”Cache LUN XP modes” on page 10
•”Pre-staging” on page 11
•”Starting Cache LUN XP” on page 12
•”Setting (creating) a cache extent” on page 14
•”Partial Cache Residence (PCR) operations” on page 17
Intended audience
This guide is intended for customers and HP authorized service providers experienced with the following:
•Disk array hardware and software
•Storage systems
Prerequisites
Prerequisites for using this product include:
•XP1024/XP128 firmware version
•Minimum:21-10-10
• Recommended: 21-14-02 or later
•Set up the HP StorageWorks XP disk arrays
•See the readme.txt file on the product CD for last-minute announcements
Related documentation
In addition to this guide, please refer to other documents for this product:
•HP StorageWorks Command View XP User Guide for XP Disk Arrays
•HP StorageWorks XP Remote Web Console User Guide for XP1024/XP128
These and other HP documents can be found on an HP web site: http://www.hp.com/support/.

6
Document conventions and symbols
CAUTION: Indicates that failure to follow directions could result in damage to equipment or data.
IMPORTANT: Provides clarifying information or specific instructions.
NOTE: Provides additional information.
TIP: Provides helpful hints and shortcuts.
HP technical support
Telephone numbers for worldwide technical support are listed on the HP web site:
http://www.hp.com/support/.
Collect the following information before calling:
•Technical support registration number (if applicable)
•Product serial numbers
•Product model names and numbers
•Applicable error messages
•Operating system type and revision level
•Detailed, specific questions
For continuous quality improvement, calls may be recorded or monitored.
HP strongly recommends that customers sign-up online using the Subscriber’s choice web site at
http://www.hp.com/go/e-updates.
Table 1 Document conventions
Convention Element
Medium blue text: Figure 1 Cross-reference links and e-mail addresses
Medium blue, underlined text
(http://www.hp.com)
Web site addresses
Bold font •Key names
•Text typed into a GUI element, such as into a box
•GUI elements that are clicked or selected, such as menu and list
items, buttons, and check boxes
Italics font Text emphasis
Monospace font •File and directory names
•System output
•Code
•Text typed at the command-line
Monospace, italic font •Code variables
•Command-line variables
Monospace, bold font Emphasis of file and directory names, system output, code, and text
typed at the command-line

Cache LUN XP user guide for the XP128/XP1024 7
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versions of drivers, and firmware documentation updates as well as instant access to numerous other
product resources.
•After signing-up, you can quickly locate your products by selecting Business support and then Storage
under Product Category.
HP-authorized reseller
For the name of your nearest HP-authorized reseller:
•In the United States, call 1-800-345-1518
•Elsewhere, visit http://www.hp.com and click Contact HP to find locations and telephone numbers
Helpful web sites
For third-party product information, see the following vendor web sites:
•http://www.hp.com
•http://www.hp.com/go/storage
•http://www.hp.com/support

8

Cache LUN XP user guide for the XP128/XP1024 9
1 Cache LUN XP for the XP128/XP1024
Use Cache LUN XP to reserve areas of cache memory on the disk array for storing high-use data from the
LDEVs. Data access speed is improved because the cache-resident data is available to the hosts at much
faster transfer speeds. This can be applied to both read and write I/O operations.
Supported volumes
Cache LUN XP works with normal volumes, LUSE volumes, and custom volumes (configured through VSC).
Use custom volumes and Cache LUN XP together to achieve higher data access performance (than when
these features are used separately).
Cache LUN XP tasks
Use Cache LUN XP to perform the following tasks:
•”Setting (creating) a cache extent” on page 14
•”Releasing (removing) a cache extent” on page 16
•”Changing an extent’s mode and pre-staging” on page 16
Figure 1 Cache LUN XP operations
Cache LUN XP requires a portion of cache memory, called the Cache LUN XP cache area. You can
change the capacity of the Cache LUN XP cache area when installing or removing cache memory.
Typically, data assigned to Cache LUN XP becomes resident (staged) in cache after it is first accessed by a
host. Then, the host finds the data in cache for the second and subsequent accesses.
Another function, called pre-staging, puts data in the Cache LUN XP cache area when the data is first set
up for caching. Pre-staging allows the host to find data in the cache at the first access.
Cache areas (also called cache extents) can be added or removed at any time. Each cache extent is
defined as a range of logical blocks within an LDEV or as an entire LDEV. Logical blocks are defined by
starting and ending Logical Block Addresses (LBAs).
Supported emulation types and other parameters
Supported emulation types
Supported open system emulation types are OPEN-3, OPEN-8, OPEN-9, OPEN-E, OPEN-L, and OPEN-V.
Supported mainframe emulation types are 3390-3, 3390-3A, 3390-3B, 3390-3C, 3390-3R, 3390-9,
3390-9A, 3390-9B, 3390-9C, 3390-L, 3390-LA, 3390-LB, and 3390-LC.
Modified volume types
LUSE (LU Size Expansion) and VSC (Volume Size Configuration) volumes can be placed in the Cache LUN
XP cache area.
If you want to apply Cache LUN XP to a LUSE volume, you must apply Cache LUN XP to all the LDEVs that
form the LUSE volume.

10 Cache LUN XP for the XP128/XP1024
Unit of cache area allocation
A Cache LUN XP extent is a range of logical blocks within an LDEV. A logical block is 512 bytes.
For OPEN-V, a cache extent must have at least 128 Logical Block Addresses (LBAs), or 66 KB. For all other
supported open system emulation types, a cache extent must have at least 96 LBAs, or 49.5 KB. This is
known as a cache slot. A cache extent can have a maximum size of an entire LDEV, up to the limits of
Cache LUN XP cache memory. Allocate data to Cache LUN XP with a minimum size of 128 LBAs for
OPEN-V and 96 LBAs for other than OPEN-V.
For mainframe systems, a cache extent must be at least one cache slot or track (48 KB or 64 KB). Its
maximum size may be an entire LDEV, up to the limits of Cache LUN XP cache memory. Allocate data to
Cache LUN XP in units of cylinders and tracks.
Number of cache areas allowed
•In DKC: 1,024
•In LDEV: 1,024
Restrictions
Cache LUN XP modes
Cache LUN XP has two modes:
•priority mode
•bind mode
Priority mode
Priority mode requires fewer cache resources but has performance limitations over bind mode. Priority
mode keeps all read data in cache (until you delete the extent) but all writes are destaged to disk normally
(using the same algorithms as for regular, non-Cache LUN XP data).
Priority mode details
•All reads following the initial read to a block will result in cache hits (100% cache read hits).
•After destaging of the write block to disk, the duplicated write areas in general cache become free.
Table 2 Restrictions
Configuration Restrictions • Do not exceed the capacity of the Cache LUN XP cache.
•Do not configure an Auto LUN XP reserved volume for Cache LUN XP.
•Do not place an LDEV in cache twice.
•You cannot allocate Cache LUN XP cache space for an on-demand LDEV.
•To apply Cache LUN XP to a LUSE volume, you must apply it to all the LDEVs
that form the LUSE volume.
Usage Restrictions • If an LDEV is placed in cache, do not use it for BC/Continuous Access XP quick
restore operations or Auto LUN XP migration. These operations may swap the
internal locations of the primary and secondary volumes and cause a loss of
data integrity.
•You cannot change a Cache LUN XP extent after it is configured. To change the
specification, you must reset (release) the Cache LUN XP extent, and then
re-allocate (set) the Cache LUN XP extent.
VSC Automatic Resets In the following cases, a Cache LUN XP cache extent is deleted (reset or released)
automatically:
•If a fixed volume, part or all of which is assigned to Cache LUN XP, is
converted into free space by the VSC Volume to Space function.
•If a custom volume, part or all of which is assigned to Cache LUN XP, is
converted into free space using the VSC Volume to Space function.
•If an LDEV (or VDEV) containing fixed and custom volumes assigned to Cache
LUN XP is initialized by the VSC Volume Initialize function.

Cache LUN XP user guide for the XP128/XP1024 11
•While destaging to disk, read requests to the same block are delayed until the disk operation is
completed.
•Priority mode generates write traffic to disk, whereas bind mode does not.
General cache capacity
In addition to the Cache LUN XP cache, you should set the general cache capacity according to the
number of areas set in priority mode. This prevents a reduction in general cache performance.
If the general cache is overloaded (having very little cache space), this can result in a wait for free cache
space. This may degrade access to the general cache.
•If you set up to 512 areas in Cache LUN XP, set 512 MB x 2 (1024 MB) of standard cache.
•If you set 513-1024 areas in Cache LUN XP, set 1024 MB x 2 (2048 MB) of standard cache.
•For OPEN-V, one slot is 66 KB, which requires 4 cache segments (16.5 KB/segment). For example,
16 slots require 1,056 KB of reserved cache.
•For other than OPEN-V, one slot is 49.5 KB, which requires 3 cache segments. For example, 16 slots
require 792 KB of reserved cache.
Bind mode
Bind mode keeps both read and write data in cache, eliminating disk traffic (100% read/write hits). All
data stays in cache until the extent is removed. The data stored in the Cache LUN XP cache is duplexed for
data protection, which requires additional Cache LUN XP cache capacity. If AC power is lost, data is
maintained in cache for up to 48 hours, using battery power.
Bind mode details
•All reads following the initial read to a block will result in cache hits.
•Duplicated write blocks are stored in cache and are never “evicted.”
•All read or write blocks stay resident in cache until the extent is deleted.
•Bind mode requires more cache because duplicated write blocks are not destaged to disk.
Bind mode and RAID groups
For RAID-5 parity groups, a Cache LUN XP extent in bind mode requires a cache capacity three times
larger than the user data.
•For OPEN-V, one slot is 66 KB, which requires 12 cache segments (16.5 KB/segment). For example,
16 slots require 3,168 KB of reserved cache.
•For other than OPEN-V, one slot is 49.5 KB, which requires 9 cache segments. For example, 16 slots
require 2,376 KB of reserved cache.
For RAID-1 parity groups, a Cache LUN XP extent in bind mode requires a cache capacity twice as large
as user data.
•For OPEN-V, one slot is 66 KB, which requires 8 cache segments (16.5 KB/segment). For example,
16 slots require 2,112 KB of reserved cache.
•For other than OPEN-V, one slot is 49.5 KB, which requires 6 cache segments. For example, 16 slots
require 1,584 KB of reserved cache.
If you want to change a RAID-1 or RAID-5 parity group’s mode from priority mode to bind mode, reset and
re-allocate the affected Cache LUN XP extent. When you re-allocate, specify the greater capacity needed
for bind mode.
Pre-staging
As mentioned before, data assigned to a Cache LUN XP cache extent becomes resident (“staged”) in
cache after it is first accessed by the host. Then, the host finds the data in cache for the second and
subsequent accesses. The pre-staging function puts data in cache before the first read. Therefore,
pre-staging allows the host to find data in cache on the first access.
Specify pre-staging when you set up the cache extent. You can use this function with either priority or bind
mode.

12 Cache LUN XP for the XP128/XP1024
You cannot change a Cache LUN XP extent after it is configured. To change the specification, you must
reset (“release”) the Cache LUN XP extent, and then re-allocate (“set”) the Cache LUN XP extent.
Starting Cache LUN XP
1. Click Cache LUN in the left pane. The Cache LUN pane appears.
Figure 2 Cache LUN pane
Cache LUN pane
This pane lists the following items:
Prestaging check box
Select or clear this check box to enable or disable the pre-staging function:
•If you select this check box, set the Prestaging Mode to Yes and click Apply. A non-pre-staging
operation will be performed and then a pre-staging operation will be performed.
•If you clear this check box and then click Apply, a non-pre-staging operation will be performed, but a
pre-staging operation will not be performed. If you select this check box later and then click Apply, only
a pre-staging operation will be performed.
When a pre-staging operation is in progress, the text Prestaging operation in progress is shown at the
bottom of the Cache LUN pane. The progress is displayed in percentage.
The Prestaging check box is enabled in Modify mode and is selected by default. However, the Prestaging
check box is disabled in either of the following conditions:
•No cache
•Prestaging mode is set to No for each cache
LDEV tree
The LDEV tree displays the CU number (for example, CU 00) and LDEV number (for example, LDEV 00)
available for Cache LUN XP operations in a tree. The tree uses the following icons to show the settings:
Table 3 Cache LUN XP icons
Icon Description
Indicates an LDEV for which Cache LUN XP is not set.
Indicates an LDEV for which Cache LUN XP is set.
Indicates a LUSE volume (two or more LDEVs) for which Cache LUN XP is not set.

Cache LUN XP user guide for the XP128/XP1024 13
The LDEV tree does not show Auto LUN-reserved volumes because they cannot be used in Cache LUN XP
operations.
LDEV table
Information about the LDEV selected in the tree appears on a single line in the upper-right portion of the
pane. It includes LDEV number, emulation type, capacity, and RAID level.
The LDEV’s capacity is shown in MB for open systems, or cylinders and tracks for mainframe systems. The
table shows the cache settings for the LDEV selected in the tree and contains the following columns:
•LBA (open systems only): Displays the logical block starting and ending addresses.
•CC HH (mainframe systems only): Displays the cylinder and head starting and ending addresses.
•Capacity: Displays the capacity of the cache extent in megabytes for open systems. Displays the
capacity of the cache extent in cylinders and tracks for mainframe systems.
•Mode: Displays the mode of the cache extent. PRIO indicates priority mode, BIND indicates bind mode,
and -indicates that the LDEV is not assigned to the cache.
•Prestage: If this is blank, then pre-staging is not set. ON indicates that pre-staging is set.
Cache LUN pie chart
The text above the pie chart lists the used cache and the amount of free space left in cache.
In the pie chart, pink indicates the amount of cache available, blue shows cache used, and yellow shows
the size of the specified cache extent.
Cache settings section
Sets the mode and area for data that will reside in the Cache LUN XP cache. Also displays the settings for
an existing cache extent. This area contains the following:
•Cache LUN Type: Select the Cache LUN XP mode by clicking either Bind or Prio.
•Prestaging Mode: Select the Prestaging check box (located above the LDEV tree) to perform the
pre-staging operation, and then click Apply. Click Yes if pre-staging is enabled. Click No if pre-staging
is disabled.
•From: The starting address for data that will reside in the cache. This is expressed as a logical block
address for open systems and as a cylinder and head address for mainframe systems.
•To: The ending address for data that will reside in the cache. This is expressed as a logical block
address for open systems and as a cylinder and head address for mainframe systems.
•Select All Area check box: If you select this check box, all data areas in the selected LDEV will be set to
Cache LUN XP cache.
This check box can be selected if no data areas in the selected LDEV are set to Cache LUN XP cache.
This check box cannot be selected and is grayed out if some data areas in the selected LDEV are set to
Cache LUN XP cache. If you select the Select All Area check box, nothing will be set to the starting
address and the ending address, and the From and To fields remain empty.
•Possible Cache LUN Size: Displays the size you can set. Bind displays the size you should set for bind
mode and Prio displays the size you should set for priority mode.
•Multi Set / Release check box: Selecting this check box and then clicking Set displays the Multi Set
pane, which you can use to make Cache LUN XP settings on more than one LDEV. Selecting this check
box and then clicking Release displays the Multi Release pane, which you can use to cancel Cache
LUN XP settings on more than one LDEV.
Data that will reside in the Cache LUN XP cache is specified by the starting address in the From field
and the ending address in the To field. When the Select All Area check box is selected, all data areas
of the selected LDEVs will be set for the Cache LUN XP.
If you cancel the settings, all the settings specified for the LDEV will be canceled.
The Multi Set / Release check box does not select and cancel an individual Cache LUN XP data area
specified for the LDEV. You must use the Release button to cancel an individual Cache LUN XP data
area.

14 Cache LUN XP for the XP128/XP1024
Buttons
•Set: Creates a cache extent.
•Release: Deletes a cache extent.
•Apply: Applies the parameters to the disk array. You can then set or release other cache extents.
•Cancel: Cancels the operation.
Setting (creating) a cache extent
1. In the LDEV tree of the Cache LUN pane, click the CU:LDEV number of the LDEV you want to put in
cache.
The LDEV table displays Cache LUN XP information for the LDEV you selected.
2. Select an area to be made resident in the Cache LUN XP cache from one of those marked “-” in the
Mode column. The Set button is enabled. The From and To boxes display the selected area’s values.
3. Click Bind or Prio to indicate the mode.
4. Click Yes or No to indicate whether to set pre-staging.
5. Complete one of the following steps:
• To place all data on an LDEV into cache, go to step 6.
• To place specific data from an LDEV into cache, go to step 7.
• To place all data on multiple LDEVs into cache, go to step 8.
• To place specific data from multiple LDEVs into cache, go to step 9.
6. To place all data on an LDEV into cache:
a. Select the Select All Area check box.
b. Clear the Multi Set / Release check box.
c. Click Set. A confirmation dialog box appears.
d. Click OK to continue. The new settings are shown in blue on the Cache LUN pane. To cancel
operations, click Cancel. Go to step 10.
7. To place specific data from an LDEV into cache:
a. If the Select All Area check box is grayed out, go to the next step. If the Select All Area check box is
activated, clear the Select All Area check box.
b. Enter the starting and ending addresses (LBAs or CC HHs) of the area to be made resident in the
cache.
For open systems, Cache LUN XP identifies a logical area in units of 128 blocks for OPEN-V, and
96 blocks for other than OPEN-V. For OPEN-V, if you have entered 1 as the starting logical block
address and a value less than 128 as the ending logical block address, Cache LUN XP
automatically changes the ending block address to 128. For other than OPEN-V, if you have
entered 1 as the starting logical block address and a value less than 96 as the ending logical block
address, Cache LUN XP automatically changes the ending block address to 96.
c. Clear the Multi Set / Release check box.
d. Click Set. A confirmation dialog box appears.
e. Click OK to continue. The new settings are shown in blue on the Cache LUN pane. To cancel
operations, click Cancel. Go to step 10.
8. To place all data on multiple LDEVs into cache:
a. Select the Select All Area check box.
b. Select the Multi Set / Release check box.
c. Click Set. A confirmation dialog box appears.

Cache LUN XP user guide for the XP128/XP1024 15
d. Click OK to continue. The Multi Set pane appears.
Figure 3 Multi Set pane
e. In the CU drop-down list, click the CU.
f. In the table, click more than one LDEV and then click Set. The Multi Set pane closes and the new
settings are shown in blue on the Cache LUN pane. To cancel operations, click Cancel. Go to
step 10.
9. To place specific data from multiple LDEVs into cache:
a. If the Select All Area check box is grayed out, go to the next step. If the Select All Area check box is
activated, clear the Select All Area check box.
b. Enter the starting and ending addresses (LBAs or CC HHs) of the area to be made resident in the
cache.
For open systems, Cache LUN XP identifies a logical area in units of 128 blocks for OPEN-V, and
96 blocks for other than OPEN-V. For OPEN-V, if you have entered 1 as the starting logical block
address and a value less than 128 as the ending logical block address, Cache LUN XP
automatically changes the ending block address to 128. For other than OPEN-V, if you have
entered 1 as the starting logical block address and a value less than 96 as the ending logical block
address, Cache LUN XP automatically changes the ending block address to 96.
c. Select the Multi Set / Release check box.
d. Click Set. A confirmation dialog box appears.
e. Click OK to continue. The Multi Set pane appears.
f. In the CU drop-down list, click the CU.
g. In the table, click more than one LDEV and then click Set. The Multi Set pane closes and the new
settings are shown in blue on the Cache LUN pane. To cancel operations, click Cancel. Go to
step 10.
10.To make data in other volumes reside in the Cache LUN XP cache, repeat the previous steps.
NOTE: You cannot use the Release button to delete the set data until you click Apply or Cancel.
11.To enable the pre-staging function, select the Prestaging check box. To disable the pre-staging function,
clear the Prestaging check box.
12.If the settings are correct, click Apply. A confirmation dialog box appears.
13.Click OK to confirm. The Cache LUN XP operation begins. If prestaging was selected, the prestaging
operation will occur next. When the operation has been completed, a confirmation dialog box
appears.
14.Click OK.

16 Cache LUN XP for the XP128/XP1024
Releasing (removing) a cache extent
1. In the LDEV tree of the Cache LUN pane, click the CU:LDEV number of the LDEV you want to remove
from cache. The LDEV table displays Cache LUN XP information about the LDEV you selected.
2. Select an extent to be removed from the Cache LUN XP cache. The Release button is enabled.
3. Complete one of the following steps:
• To remove specific data from cache, go to step 4.
• To remove all data from cache, go to step 5.
4. To remove specific data from cache:
a. Click Release. A confirmation dialog box appears.
b. Click OK to continue. The new settings are shown in blue on the Cache LUN pane. To cancel
operations, click Cancel. Go to step 6.
5. To remove all data from cache
a. Select the Multi Set / Release check box.
b. Click Release. A confirmation dialog box appears.
c. Click OK to continue. The Multi Release window appears.
Figure 4 Multi Release pane
d. In the CU box, click the CU.
e. In the table, click more than one LDEV and then click Release. The Multi Release pane closes and
the new settings are shown in blue on the Cache LUN pane. To cancel operations, click Cancel. Go
to step 6.
6. To remove cache data for another CU:LDEV, repeat the previous steps.
7. If the deletions are correct, click Apply. A confirmation dialog box appears.
8. Click OK to confirm. The Cache LUN XP operation begins. If prestaging was selected, the prestaging
operation will occur next. When the operation has been completed, a confirmation dialog box
appears.
9. Click OK.
Changing an extent’s mode and pre-staging
You cannot directly change a cache extent’s mode or pre-staging settings. You must delete the extent and
reconfigure it with new settings.
1. Select and release (remove) the extent in the Cache LUN XP cache.
2. Remake the extent with the new mode and pre-staging settings.

Cache LUN XP user guide for the XP128/XP1024 17
Partial Cache Residence (PCR) operations
Overview of the PCR function
The XP128/XP1024 has a special network board that allows the array to be connected directly to a LAN.
This network connection interface is called Network Attached Storage (NAS).
The NAS disk array uses a cache to store two types of data:
•Management information (called i-node), including information on managing file system directories
and file pointers
•Log information, used by the NAS channel file system to improve performance of data throughput in the
LAN via the NAS channel
This cache function is called Partial Cache Residence (PCR). A PCR cache is assigned to each channel,
and the PCR cache is shared and used by all files that are accessed through NAS channels. User data
transferred through a NAS channel uses the ordinary cache area. Figure 5 shows the PCR cache area
(cache extent).
Figure 5 PCR cache area (cache extent)
PCR operations
To perform PCR operations, you must belong to the Administrators or StorageAdmins group. If you belong
to the Users group, you can only view PCR information.
NOTE: Only users belonging to the Administrators group are permitted to make modifications to arrays.
1. Click Cache LUN in the left pane. The Cache LUN pane appears.

18 Cache LUN XP for the XP128/XP1024
2. Click the PCR tab. The PCR pane appears.
Figure 6 PCR Pane
PCR pane
The PCR pane displays the table of NAS channels available for PCR operations, as well as a pie chart
showing PCR cache usage. You can set the PCR cache size for management information (i-node) and log
information used by the NAS channel file system.
This pane lists the following items:
•The PCR information table shows the PCR cache size for both management information (i-node) and log
information files used to manage data on NAS channels.
•TheCHN column displays the name of the NAS channel.
•Thei-node column displays the cache size assigned to the area used by the NAS channel file
system for two types of management: current status management (i-node) and directory
management.
•Thelog column displays the cache size assigned to the area used for obtaining log information on
NAS channels.
•The PCR information area, located above the pie chart, displays two fields with PCR cache usage
information:
•Available Partial Cache Residence Size: The amount of the PCR cache available for use (pink area
in the pie chart).
•Used Partial Cache Residence Size: The amount of PCR cache currently in use (blue and/or yellow
areas in the pie chart).
•The pie chart uses the following colors:
•Blue: Shows PCR cache usage
•Yellow: Shows the increase in the specified size of the PCR cache
•Pink: Shows the remaining amount of available PCR cache
•The PCR operations box, located on the lower right corner of the PCR main panel, allows you to set the
PCR cache size for both management information (i-node) and log information used by the NAS
channel selected in the PCR information table. You can select several NAS channels at once.
•Usethei-node field to enter the amount of cache assigned to the area used by the NAS channel file
system for current status management (i-node) and directory management.
•Usethelog field to enter the amount of cache assigned to the area used for obtaining log
information on NAS channels.

Cache LUN XP user guide for the XP128/XP1024 19
•Buttons:
•Set: Adds the requested PCR operation (set PCR cache) to the PCR information table.
•Clear: Enters 0 (zero) into both the i-node and log fields.
•Apply: Starts the requested operations listed in the PCR information table.
•Cancel: Cancels the requested operations and resets the PCR information table.
Viewing the current PCR settings
You can view the current PCR settings in the PCR pane.
•The PCR information table shows the current PCR cache size for management information (i-node) and
for log information files that are used to manage data on NAS channels.
•The 3D pie chart shows current cache usage.
Setting the PCR cache for management information (i-node) and log information
1. Connect to the desired disk array and log on with Administrator or PCR write access.
2. Open the PCR pane.
3. Click the desired NAS channel in the PCR information table. You can select more than one channel at
a time.
Figure 7 PCR pane
4. Enter desired values (the capacities of PCR cache) in the i-node and log fields.
NOTE: If you want to enter 0 (zero) in both boxes, click the Clear button.
5. Click Set. A confirmation message appears.
6. Click OK to continue your operations. The requested PCR operation appears in blue bold italics in the
PCR information table.
7. Repeat step 3 - step 6 until all desired operations are listed.
8. Review the requested operations in the PCR pane.
• To start the operations, click Apply in the PCR pane. The Apply confirmation message appears.
•ClickOK. The Complete confirmation message appears.
• To cancel the operations, click Cancel in the PCR pane, and then click OK in the Cancel
confirmation message.
9. To confirm the operations, click OK in the Complete confirmation message. The PCR pane appears.
10.Monitor the PCR pane to make sure the operations were successful.

20 Cache LUN XP for the XP128/XP1024