HP XP 9000 User manual

HP
XP 9000 Cache Partition User Guide
Abstract
This guide describes how to use the HP XP P9000 Cache Partition Software on HP XP P9000 disk arrays. The intended audience
is a storage administrator or authorized service provider with independent knowledge of HP XP P9000 disk arrays and HP XP
P9000 software.
HP Part Number: AV400-96477
Published: August 2012
Edition: Eighth

© Copyright 2011, 2012 Hewlett-Packard Development Company, L.P.
Confidential computer software. Valid license from HP required for possession, use or copying. Consistent with FAR 12.211 and 12.212, Commercial
Computer Software, Computer Software Documentation, and Technical Data for Commercial Items are licensed to the U.S. Government under
vendor's standard commercial license.
The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express
warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall
not be liable for technical or editorial errors or omissions contained herein.
This document is intended for system administrators and HP representatives who are involved in installing, configuring, and operating the P9500
storage system.
Readers of this document should meet the following requirements:
•Understand RAID storage systems and their basic functions.
•Be familiar with the HP XP P9000 Owner Guide.
•Be familiar with the Remote Web Console software.
Acknowledgements
Microsoft®, Windows®, Windows® XP, and Windows NT® are U.S. registered trademarks of Microsoft Corporation.
Export Requirements
You may not export or re-export this document or any copy or adaptation in violation of export laws or regulations.
Without limiting the foregoing, this document may not be exported, re-exported, transferred or downloaded to or within (or to a national resident
of) countries under U.S. economic embargo, including Cuba, Iran, North Korea, Sudan, and Syria. This list is subject to change.
This document may not be exported, re-exported, transferred, or downloaded to persons or entities listed on the U.S. Department of Commerce
Denied Persons List, Entity List of proliferation concern or on any U.S. Treasury Department Designated Nationals exclusion list, or to parties directly
or indirectly involved in the development or production of nuclear, chemical, biological weapons, or in missile technology programs as specified
in the U.S. Export Administration Regulations (15 CFR 744).
Revision History
DescriptionDateEdition
Applies to microcode version 70-01-01-00/00 or later.October 2010First
Applies to microcode version 70-01-24-00/00 or later.November 2010Second
Applies to microcode version 70-01-62-00/00 or later.January 2011Third
Applies to microcode version 70-02-01-00/00 or later.May 2011Fourth
Applies to microcode version 70-02-7x-00/00 or laterSeptember 2011Fifth
Applies to microcode version 70-03-00-00/00 or later.November 2011Sixth
Applies to microcode version 70-03-3x-00/00 or later.April 2012Seventh
Applies to microcode version 70-04-00-00/00 or later.August 2012Eighth

Contents
1 Creating virtual cache partitions...................................................................4
About virtual cache partitions.....................................................................................................4
Cache capacity for a CLPR........................................................................................................4
Cache partitioning rules and guidelines.......................................................................................7
Partitioning cache.....................................................................................................................9
Cache partition work flows....................................................................................................9
Creating a CLPR..................................................................................................................9
Migrating resources to and from a CLPR................................................................................10
Deleting a CLPR ................................................................................................................11
2 Troubleshooting........................................................................................12
Troubleshooting Cache Partition................................................................................................12
3 Support and other resources......................................................................13
Contacting HP........................................................................................................................13
Subscription service............................................................................................................13
Documentation feedback....................................................................................................13
Related information.................................................................................................................13
HP websites......................................................................................................................13
Conventions for storage capacity values....................................................................................14
Typographic conventions.........................................................................................................14
A Cache Partition GUI reference....................................................................16
Partition Definition tab (Storage System selected).........................................................................16
Partition Definition tab, Cache Logical Partition window (CLPR selected).........................................17
Partition Definition tab, Cache Logical Partition window (each CLPR information).............................17
Select CU dialog box..............................................................................................................19
Glossary....................................................................................................21
Index.........................................................................................................22
Contents 3

1 Creating virtual cache partitions
This topic provides detailed instructions for dividing storage system cache memory into virtual
cache logical partitions (CLPRs) using Cache Partition software.
About virtual cache partitions
If one storage system is shared with multiple hosts, one host reading or writing a large amount of
data can require enough of the storage system’s cache memory to affect other users. The Cache
Partition function allows improved I/O performance by dividing storage system cache memory
into multiple virtual cache memories (cache logical partitions or CLPRs).
Partitioning cache matches data to appropriate storage resources based on availability,
performance, capacity, and cost. It improves flexibility by allowing dynamic changes to cache
partitions while in use.
Partitioning cache dedicates cache resources for exclusive use by specific applications to maintain
priority and quality of service for business-critical applications. Storage administrators can secure
and/or restrict access to storage resources to ensure confidentiality for specific applications. By
dedicating resources to each partition as needed, a high quality of service can be maintained for
all users.
The following illustrates the use of cache memory within a corporation. In this example, cache
memory is partitioned into three segments of 40 GB, each of which is allocated to a branch office.
The host of branch A has a heavy I/O load. Because the cache memory is partitioned, that heavy
I/O load does not impact the cache memory for the other two branches.
Cache capacity for a CLPR
A CLPR is a pool of the cache and parity groups in the storage system. Partitioning cache into one
or more CLPRs allows storage administrators to dedicate individual CLPRs to a different host,
preventing I/O contention for cache memory.
Before you partition cache memory into CLPRs, calculate the cache capacity that will be needed
on your storage system. If necessary, install additional cache memory.
When you create a CLPR, the recommended cache capacity is determined by the conditions such
as: the number of mounted processor blades, RAID level, the number of drives that are installed
4 Creating virtual cache partitions

on the storage system, and whether Thin Provisioning, Smart Tiers, Cache Residency, Compatible
XRC, or External Storage is used or not (enabled or disabled).
Calculate the recommended cache capacity for a CLPR using the formula below:
Recommended cache capacity (GB) for a CLPR = (CLPR capacity (GB) – ceiling (Cache Residency
extents (MB)/ 2,048) × 2 GB)
(i) When Thin Provisioning, Smart Tiers, Cache Residency or Compatible XRC
is not used:
When you do not use any of Thin Provisioning, Smart Tiers, Cache Residency, or Compatible XRC
for a CLPR, see the table below for the recommended cache capacity.
Recommended cache capacity for a CLPRNumber of processor bladesTotal capacity of internal VOL* and
external VOL for a CLPR
7 GB or more2Less than 1,500 GB
15 GB or more4
22 GB or more6
30 GB or more8
8 GB or more21,500 GB or more
15 GB or more4
22 GB or more6
30 GB or more8
16 GB or more2 or 42,900 GB or more
22 GB or more6
30 GB or more8
22 GB or more2, 4 or 611,500 GB or more
30 GB or more8
24 GB or more2, 4 or 614,400 GB or more
30 GB or more8
30 GB or more2, 4, 6 or 8100,000 GB or more
32 GB or more128,000 GB or more
40 GB or more182,000 GB or more
48 GB or more218,000 GB or more
56 GB or more254,000 GB or more
64 GB or more290,000 GB or more
72 GB or more326,000 GB or more
* Calculate the internal volume capacity for a CLPR using the formula below.
Internal volume capacity = number of (3D+1P) parity groups x capacity of one HDD x 3 + number of (6D+2P) parity
groups x capacity of one HDD x 6 + number of (7D+1P) parity groups x capacity of one HDD x 7 + number of
(14D+2P) parity groups x capacity of one HDD x 14 + number of (2D+2D) parity groups x capacity of one HDD x 2
When you use an external volume or a virtual volume, you cannot use the above formula. If you
use an external volume, calculate the total capacity of parity groups that are associated with the
CLPR. If you use a virtual volume, calculate the total LDEV capacity of the virtual volume that is
Cache capacity for a CLPR 5

associated with the CLPR. To check the LDEV capacity of the virtual volume, see the LDEV dialog
box in the Basic Information Display dialog box of the Remote Web Console subwindow. For
further information about Remote Web Console subwindow, see the HP XP P9000 Remote Web
Console User Guide.
(ii) When Thin Provisioning or Smart Tiers is used:
When you use Thin Provisioning or Smart Tiers for a CLPR, see the table below for the recommended
cache capacity.
Recommended cache capacity for a CLPRNumber of processor bladesTotal capacity of internal VOL* and
external VOL for a CLPR
12 GB or more2Less than 2,900 GB or more
22 GB or more4
22 GB or more6
42 GB or more8
16 GB or more22,900 GB or more
22 GB or more4
32 GB or more6
42 GB or more8
22 GB or more2 or 411,500 GB or more
32 GB or more6
42 GB or more8
24 GB or more2 or 414,400 GB or more
32 GB or more6
42 GB or more8
32 GB or more2, 4, or 6100,000 GB or more
42 GB or more8
32 GB or more2, 4, or 6128,000 GB or more
42 GB or more8
42 GB or more2, 4, 6, or 8182,000 GB or more
48 GB or more218,000 GB or more
56 GB or more254,000 GB or more
64 GB or more290,000 GB or more
72 GB or more326,000 GB or more
* Calculate the internal volume capacity for a CLPR using the formula below.
Internal volume capacity = number of (3D+1P) parity groups x capacity of one HDD x 3 + number of (6D+2P) parity
groups x capacity of one HDD x 6 + number of (7D+1P) parity groups x capacity of one HDD x 7 + number of
(14D+2P) parity groups x capacity of one HDD x 14 + number of (2D+2D) parity groups x capacity of one HDD x 2
(iii) When Cache Residency is used:
When you use the Priority mode by using Cache Residency for a CLPR, you may want to add
cache capacity depending on the number of areas in which the priority mode is set in addition to
the cache used for Cache Residency. For further information, see the Priority mode section of the
HP XP P9000 Performance for Open and Mainframe Systems User Guide.
6 Creating virtual cache partitions

(iv) When Compatible XRC is used:
When you use Compatible XRC for a CLPR, cache capacity for administrative information called
sidefile is needed. Therefore, you may want to add larger cache capacity than the recommended
cache capacity calculated from (i), (ii), or (iii) with sleep wait threshold in mind.
Calculate the recommended capacity using the formula below:
Recommended cache capacity = (Recommended cache capacity calculated from (i)-(iii)) × 100 /
(100 - (Sleep wait threshold))
(v) When only External Storage is used:
If the CLPR to be created meets the following conditions, the recommended cache memory capacity
in the table below can be applied.
•The CLPR uses only external volumes.
•The transfer speed is not emphasized.
•The cache mode of the mapped volume is Disable.
•The CLPR uses only volumes that are for Open systems.
Recommended cache capacity for a
CLPR
Number of processor
blades
Total capacity of external volume of CLPR in which
only Ext Stor is used
4 GB2 or 4Less than 128,000
8 GB6 or 8
8 GB2 or 4128,000 or more
16 GB6 or 8
When adding cache memory, use either the Standard Cache Access Model mode or the High
Performance Cache Access Model mode. If your storage system has any additional printed circuit
boards (PCBs), you must use the High Performance Cache Access Model mode. For more information
about adding cache memory, contact the HP Technical Support.
Cache partitioning rules and guidelines
Observe the following rules, restrictions, and guidelines when creating cache logical partitions:
For the priority mode cache requirements, see the HP XP P9000 Performance for Open and
Mainframe Systems User Guide.
You can operate Cache Partition from Remote Web Console or RAID Manager. To use RAID
Manager, see the HP XP P9000 RAID Manager User Guide.
Rules
•Cache Partition must be enabled on your system.
•CLPR0 is the default CLPR in a storage system. If you have not yet created any cache logical
partitions, all cache belongs to CLPR0.
•Usually, you can create a CLPR if the storage system has 4 GB cache. However, when creating
a CLPR while using Cache Residency, the remaining cache size, which is calculated by
subtracting Cache Residency size from the cache size of CLPR0, must be 8 GB or more.
•Adding or changing CLPR definitions or configurations may take hours to implement and
cannot be canceled or modified until all changes are complete. For assistance or for more
information, contact your HP account team.
Cache partitioning rules and guidelines 7

Restrictions
The following operations are not allowed when multiple CLPRs are involved:
•Creating LUSE volumes across multiple CLPRs. If you forcibly perform this operation and create
a LUSE across multiple CLPRs, the LUSE volumes cannot be used for Continuous Access
Synchronous or Continuous Access Synchronous Z pair volumes.
•Business Copy Quick Restore operations that affect multiple CLPRs.
•Auto LUN manual migration operations that affect multiple CLPRs.
•A parity group containing LDEVs assigned to Cache Residency cache extents (cache areas)
cannot be migrated to another CLPR. See the HP XP P9000 Performance for Open and
Mainframe Systems User Guide for more information about cache extents.
•If you are using Continuous Access Journal, Continuous Access Journal data volumes and
journal volumes can belong to different CLPRs. All journal volumes in the same journal must
belong to the same CLPR. If not, an error occurs.
Guidelines
•Install any needed additional cache memory before partitioning cache. It will be difficult to
add additional cache memory after partitioning cache into CLPRs.
•If the cache capacity of defined CLPR is decreased by the Cache Residency cache area, cancel
Cache Residency bind mode setting, change the cache capacity of CLPR, and then set the
bind mode or priority mode again.
•Best practice is to create cache logical partitions either during the initial installation and setup
or during a maintenance window, because cache logical partition operations can significantly
degrade host performance. If you must perform such operations on a production machine,
use Performance Monitor to verify that the write pending rate, including spikes, is well below
30%.
The table below shows CLPR names set by default to associated CLPR numbers. Because CLPR
names are reserved, they cannot be set to alternative CLPR numbers. For example, "CLPR2" cannot
be set to the CLPR number 1.
CLPR nameCLPR numberCLPR nameCLPR number
CLPR1616CLPR00
CLPR1717CLPR11
CLPR1818CLPR22
CLPR1919CLPR33
CLPR2020CLPR44
CLPR2121CLPR55
CLPR2222CLPR66
CLPR2323CLPR77
CLPR2424CLPR88
CLPR2525CLPR99
CLPR2626CLPR1010
CLPR2727CLPR1111
CLPR2828CLPR1212
CLPR2929CLPR1313
8 Creating virtual cache partitions

CLPR nameCLPR numberCLPR nameCLPR number
CLPR3030CLPR1414
CLPR3131CLPR1515
Partitioning cache
Cache partition work flows
Creating a CLPR
1. Create a CLPR (see “Creating a CLPR” (page 9)).
2. Migrate resources to the new CLPR (see “Migrating resources to and from a CLPR” (page 10)).
Removing a CLPR
1. Migrate resources from the CLPR that is to be removed (see “Migrating resources to and from
a CLPR” (page 10)).
2. Delete the CLPR (see “Deleting a CLPR ” (page 11)).
Creating a CLPR
Before creating a CLPR, review “Cache partitioning rules and guidelines” (page 7).
1. Click Settings >Environmental Setting >Partition Definition on the menu bar of the Remote
Web Console main window.
2. Click to change the mode from View to Modify.
3. In Cache Partition, open the Partition Definition window, and select a CLPR in the Partition
Definition tree.
4. In the Cache Logical Partition window, right-click a CLPR from the Partition Definition tree and
select Create CLPR. This adds a cache logical partition to the Partition Definition tree. The
maximum number of CLPRs that can be manually created is 31 (not including CLPR0).
5. Select the newly created CLPR to open the Cache Logical Partition window.
Partitioning cache 9

6. In the Detail for CLPR in Storage System section, do the following:
•In CLPR Name field, type the name of the cache logical partition, in up to 16 alphanumeric
characters. However, it cannot be changed to the CLPR name that is reserved for the
storage system. See “Cache partitioning rules and guidelines” (page 7).
•In Cache Size, select the cache capacity. You may select from 4 to 508 GB, in 2 GB
increments. The default value is 4 GB. The size of the cache is allocated from CLPR 0,
but you must leave at least 8 GB remaining in CLPR 0.
•In Cache Residency Size, select the cache capacity. You may select from 4 to 508 GB,
in 2 GB increments. The default value is 4 GB. The size of the cache is allocated from
CLPR0, but you must leave at least 8 GB remaining in CLPR0.
•In Num of Cache Residency Areas, type the desired capacity for the Cache Residency
area. The range of values is 0 to 16384 and the default value is 0.
7. Click Apply. The progress bar appears. The change in cache capacity is reflected in this cache
logical partition and in the CLPR0.
8. To change the settings of an existing CLPR, repeat steps 5 through 7.
At this point, the CLPR has no parity groups. You can now migrate resources to the new CLPR (see
“Migrating resources to and from a CLPR” (page 10)).
Migrating resources to and from a CLPR
After adding a CLPR, you must migrate resources (parity groups) from existing CLPRs to the new
CLPR. Before deleting a CLPR, you must first migrate resources from that CLPR to CLPRs that will
not be deleted.
When migrating resources to and from cache logical partitions:
•You can migrate resources only within the same CU.
•All interleaved parity groups must be in the same CLPR.
•LUSE volumes cannot be set across more than one CLPR.
•If a parity group contains one or more LDEVs that have defined Cache Residency extents, you
cannot migrate that parity group to another CLPR.
To migrate resources to and from a CLPR:
1. Click Settings >Environmental Setting >Partition Definition on the menu bar of the Remote
Web Console main window.
2. Click to change the mode from View to Modify.
3. Access the Logical Partition window, then select a CLPR from the Partition Definition tree.
4. In the Cache Logical Partition window, click Select CU to choose a CU.
5. Specify how you want to view information the CLPR resource list. In the Select CU dialog box,
choose one of the following:
•All CUs: Shows the information about all CUs on the CLPR resource list.
•Choose Specific CU, then specify the LDKC and the CU. This shows only CLPRs from the
selected CU.
•Unallocated: Shows information about only the CUs unallocated to CLPR on the CLPR
resource list.
10 Creating virtual cache partitions