Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide
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ii Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Contents
Preface ...... ix Intended audience...... x Product version ...... x Document revision level ...... x Referenced documents...... x Changes in this revision ...... xi Document organization ...... xi Document conventions...... xii Convention for storage capacity values ...... xiii Accessing product documentation ...... xiii Getting help ...... xiv Comments ...... xiv
1 Overview of Copy-on-Write Snapshot ...... 1-1 Copy-on-Write Snapshot software ...... 1-2 How Copy-on-Write Snapshot works ...... 1-2 Volume pairs: P-VOLs and V-VOLs ...... 1-2 Data pools ...... 1-4 Components ...... 1-4 Licenses and capacity ...... 1-4 Consistency groups ...... 1-5 Interfaces for performing Copy-on-Write Snapshot operations ...... 1-5 The Storage Navigator ...... 1-5 Command Control Interface ...... 1-6 Pair status ...... 1-6
2 Copy-on-Write Snapshot planning and design ...... 2-1 Consistency group system requirements ...... 2-2 Data pool requirements and restrictions...... 2-4 Planning pair volumes ...... 2-5 Planning V-VOLs and data pools ...... 2-5
iii Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Sizing the data pool workflow ...... 2-6 Calculating the number of Copy-on-Write Snapshot pairs ...... 2-7 Calculating SS pairs when creating external volumes or V-VOLs ...... 2-7 Calculating maximum SS pairs based on differential tables workflow . . . . . 2-7 Calculating maximum SS pairs based on shared memory workflow...... 2-9 Calculate the capacity of the pool management block ...... 2-11 Capacity of pool association information ...... 2-12 Calculating maximum pairs based on pair tables...... 2-12 Determining maximum pairs allowed on your system ...... 2-12 Planning for splitting pairs in consistency groups ...... 2-12 Requirements and restrictions for the At-Time Split operation ...... 2-13 Pair inclusion in At-Time Split operations workflow ...... 2-13 Consistency maintenance workflow when sharing SS P-VOLs with UR or TC volumes ...... 2-14 Snapshot secondary volume consistency maintenance ...... 2-16 External volumes...... 2-16 External-volume failures...... 2-17
3 Copy-on-Write Snapshot installation and configuration ...... 3-1 Installing and removing Copy-on-Write Snapshot ...... 3-2 Configuration workflow ...... 3-2 Creating data pools ...... 3-2 Creating V-VOLs ...... 3-4 Setting up the Command Control Interface command device ...... 3-5
4 Sharing Copy-on-Write Snapshot volumes...... 4-1 Interoperability with other software applications and functions ...... 4-2 The Data Retention Utility and access attributes...... 4-3 Dynamic Provisioning...... 4-4 Resource Partition Manager ...... 4-5 ShadowImage...... 4-5 Restrictions when sharing P-VOLs ...... 4-7 TrueCopy and Universal Replicator ...... 4-7 TC and UR volume backup in 3DC multi-target configuration ...... 4-8 Volume Migration ...... 4-9 Thin Image...... 4-9
5 Pair operations...... 5-1 Pair operations ...... 5-2 Checking the pair status ...... 5-2 Pair creation workflow ...... 5-2 Pair creation ...... 5-3 Configuring pairs...... 5-3 Removing and moving volumes...... 5-4
iv Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Creating pairs ...... 5-5 Pair split ...... 5-9 Splitting pairs ...... 5-10 Splitting pairs in consistency groups at a pre-determined time ...... 5-10 Pair resynchronization and restoration ...... 5-11 Resynchronizing and restoring pairs ...... 5-11 Pair deletion ...... 5-12 Deleting pairs ...... 5-12
6 Copy-on-Write Snapshot monitoring and maintenance ...... 6-1 Monitoring the storage system ...... 6-2 Monitoring pair information, license capacity, status ...... 6-2 Pair status definitions ...... 6-2 Monitoring pair properties ...... 6-3 Monitoring synchronous rates ...... 6-4 Monitoring consistency groups ...... 6-4 Monitoring pair operations history ...... 6-4 Monitoring pool information ...... 6-5 Maintaining the storage system...... 6-6 Managing data pools ...... 6-6 Increasing data pool volume capacity ...... 6-6 Changing pool volume threshold ...... 6-7 Changing pool volume names ...... 6-7 Recovering pool volumes ...... 6-8 Deleting pool volumes ...... 6-8 Managing virtual volumes...... 6-8 Changing virtual volume names ...... 6-9 Deleting virtual volumes ...... 6-9 Switching off the storage system power and replacing the microcode . . . 6-10 Switching off the power supply ...... 6-10 Replacing the microcode offline...... 6-10
7 Copy-on-Write Snapshot troubleshooting ...... 7-1 General troubleshooting ...... 7-2 Recovering from failure during pairresync -restore operation ...... 7-6 Recovering a terminated HP-UX host server ...... 7-6 Recovering a blocked pool workflow ...... 7-6 Pool-related SIM entry removal workflow ...... 7-7 Completing Service Information Messages ...... 7-7 Troubleshooting with Command Control Interface...... 7-8 Identifying errors using the log on the CCI window...... 7-15 Identifying errors using the Command Control Interface operation log file. 7-16
v Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide A Command Control Interface command reference...... A-1 Command Control Interface commands for Storage Navigator operations . . . . . A-2 Storage Navigator and Command Control Interface pair status names ...... A-2 Statuses required for Command Control Interface pair operations ...... A-2
B Copy-on-Write Snapshot GUI reference ...... B-1 Pools window ...... B-2 Selected pool volume window...... B-6 Create Pools wizard ...... B-15 Create Pools window ...... B-16 Confirm window ...... B-21 Expand Pool wizard ...... B-22 Expand Pool window ...... B-22 Confirm window ...... B-24 Edit Pools wizard...... B-25 Edit Pools window ...... B-25 Confirm window ...... B-27 Delete Pools wizard ...... B-29 Delete Pools window ...... B-29 Confirm window ...... B-31 Restore Pools window ...... B-32 Complete SIMs window ...... B-33 Select Pool window ...... B-34 Select Pool Volumes window...... B-35 Pool Property window ...... B-39 Create Pairs wizard ...... B-40 Select Pair Configuration window ...... B-40 Select Primary Volumes window ...... B-41 Select Pool window ...... B-45 Select Secondary Volumes window ...... B-46 Edit Mirror Units window ...... B-48 Confirm window ...... B-49
C Pair operations (secondary window) ...... C-1 Pair operations workflow ...... C-2 Checking pair status ...... C-2 Creating a pair ...... C-2 Creating pairs in a consistency group ...... C-3 Splitting pairs ...... C-4 Resynchronizing pairs ...... C-4 Restoring pairs ...... C-5 Deleting pairs ...... C-5 Deleting a single pair ...... C-5 Deleting multiple pairs related to a port or host group ...... C-5 Deleting multiple pairs related to a pool...... C-6 vi Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide D Copy-on-Write Snapshot monitoring and maintenance (secondary window) ...... D-1 Monitoring the system in the secondary window...... D-2 Monitoring pair status ...... D-2 Pair status definitions ...... D-3 Statuses required for pair operations ...... D-3 Monitoring pair volume details ...... D-3 Monitoring S-VOL path information ...... D-5 Monitoring number of pairs and license information ...... D-6 Monitoring pair operation history...... D-8 Maintaining the system ...... D-9
E Copy-on-Write Snapshot GUI reference (secondary window) . . . . . E-1 Pair Operation window ...... E-2 Volume list ...... E-3 Preview list ...... E-5 Command menu ...... E-6 History window ...... E-6 Reference codes ...... E-8 C.O.W. Snapshot window ...... E-8
Glossary
Index
vii Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide viii Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Preface
This guide provides instructions for performing Copy-on-Write Snapshot (SS) tasks on Hitachi Virtual Storage Platform (VSP) storage systems. Notice: The use of the features and/or software applications described in this guide and all other Hitachi Data Systems software applications is governed by the terms of your agreements with Hitachi Data Systems.
□ Intended audience
□ Product version
□ Document revision level
□ Referenced documents
□ Changes in this revision
□ Document organization
□ Document conventions
□ Convention for storage capacity values
□ Accessing product documentation
□ Getting help
□ Comments
Preface ix Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Intended audience This document is intended for system administrators, Hitachi Data Systems representatives, and authorized service providers who are involved in installing, configuring, and operating the Hitachi Virtual Storage Platform storage system. Readers of this document should meet the following requirements: • Have a background in data processing and understand RAID storage systems and their basic functions. • Be familiar with the Hitachi Virtual Storage Platform storage system, and have read the Hitachi Virtual Storage Platform User and Reference Guide. • Be familiar with the Storage Navigator (SN) software for the Hitachi Virtual Storage Platform storage system and have read the Hitachi Storage Navigator User Guide.
Product version This document revision applies to Hitachi Virtual Storage Platform microcode 70-06-2x or later. You must have Storage Administrator (Local Copy) role to perform Compatible FlashCopy® V2 operations in the SN.
Document revision level
Revision Date Description
MK-90RD7013-00 October 2010 Initial release. MK-90RD7013-01 December 2010 Supersedes and replaces MK-90RD7013-00. MK-90RD7013-02 April 2011 Supersedes and replaces MK-90RD7013-01. MK-90RD7013-03 August 2011 Supersedes and replaces MK-90RD7013-02. MK-90RD7013-04 November 2011 Supersedes and replaces MK-90RD7013-03. MK-90RD7013-05 March 2012 Supersedes and replaces MK-90RD7013-04. MK-90RD7013-06 June 2012 Supersedes and replaces MK-90RD7013-05. MK-90RD7013-07 November 2012 Supersedes and replaces MK-90RD7013-06. MK-90RD7013-08 January 2013 Supersedes and replaces MK-90RD7013-07. MK-90RD7013-09 July 2013 Supersedes and replaces MK-90RD7013-08. MK-90RD7013-10 December 2013 Supersedes and replaces MK-90RD7013-09. MK-90RD7013-11 September 2014 Supercedes and replaces MK-90RD7013-10
Referenced documents Hitachi Virtual Storage Platform documentation: • Hitachi Command Control Interface Installation and Configuration Guide, MK-90RD7008
x Preface Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide • Hitachi Command Control Interface User and Reference Guide, MK- 90RD7010 • Hitachi Virtual Storage Platform Provisioning Guide for Open Systems, MK-90RD7022 • Hitachi ShadowImage® User Guide, MK-90RD7024 • Hitachi Storage Navigator User Guide, MK-90RD7027 • Hitachi Storage Navigator Messages, MK-90RD7028 • Hitachi Universal Volume Manager User Guide, MK-90RD7032 • Hitachi Virtual Storage Platform User and Reference Guide, MK- 90RD7042
Changes in this revision • Added error codes 97D6 and 97D7 to Troubleshooting with Command Control Interface on page 7-8.
Document organization The following table provides an overview of the contents and organization of this document. Click the chapter title in the Chapter column to go to that chapter. The first page of each chapter provides links to the sections in that chapter.
Chapter Description
Overview of Copy-on- Provides an overview of SS. Write Snapshot on page 1-1 Copy-on-Write Snapshot Describes the storage system and operational planning and design on requirements. page 2-1 Copy-on-Write Snapshot Provides instructions for installing and configuring SS. installation and configuration on page 3-1 Sharing Copy-on-Write Provides information about sharing SS volumes with other Snapshot volumes on Hitachi Data Systems features and software applications. page 4-1 Pair operations on page 5- Provides instructions for pair operations. 1 Copy-on-Write Snapshot Provides instructions for monitoring and maintaining pairs. monitoring and maintenance on page 6-1 Copy-on-Write Snapshot Provides troubleshooting information. troubleshooting on page 7-1 Command Control Provides command line interface (CLI) commands for SS Interface command operations. reference on page A-1
Preface xi Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Chapter Description
Copy-on-Write Snapshot Describes SS windows and dialog boxes in SN. GUI reference on page B- 1 Pair operations Provides instructions for pair operations using the previous (secondary window) on SN graphical user interface (GUI), which opens in a page C-1 secondary window. Copy-on-Write Snapshot Provides information for checking status and other monitoring and information using the previous SN GUI, which opens in a maintenance (secondary secondary window. window) on page D-1 Copy-on-Write Snapshot Describes SS windows and dialog boxes in the previous SN GUI reference (secondary GUI, which opens in a secondary window. window) on page E-1
Document conventions This document uses the following typographic conventions:
Convention Description
Bold Indicates text on a window or dialog box, including window and dialog box names, menus, menu options, buttons, items, and labels. Example: Click OK. Italic Indicates a variable, which is a placeholder for actual text provided by the user or system. Example: copy source-file target-file Note: Angled brackets (< >) are also used to indicate variables. screen/code Indicates text that is shown on screen or entered by the user. Example: # pairdisplay -g oradb < > angled brackets Indicates a variable, which is a placeholder for actual text provided by the user or system. Example: # pairdisplay -g
This document uses the icons in the following table to draw attention to information:
xii Preface Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Icon Meaning Description
Tip Provides helpful information, guidelines, or suggestions for performing tasks more effectively.
Note Calls attention to important and/or additional information.
Caution Warns users of adverse conditions and consequences, such as disruptive operations.
WARNING Warns users of severe conditions and consequences, such as destructive operations.
Convention for storage capacity values Physical storage capacity values (such as disk drive capacity) are calculated based on the following values:
Physical capacity unit Value
1 KB 1,000 bytes
1 MB 1,00002 bytes
1 GB 1,0003 bytes
1 TB 1,0004 bytes
1 PB 1,0005 bytes
1 EB 1,0006 bytes
Logical storage capacity values (such as logical device capacity) are calculated based on the following values:
Logical capacity unit Value
1 KB 1,024 bytes
1 MB 1,024 KB or 1,0242 bytes
1 GB 1,024 MB or 1,0243 bytes
1 TB 1,024 GB or 1,0244 bytes
1 PB 1,024 TB or 1,0245 bytes
1 EB 1,024 PB or 1,0246 bytes 1 block 512 bytes
Accessing product documentation The Hitachi Virtual Storage Platform user documentation is available on the Hitachi Data Systems Support Portal: https://portal.hds.com. Please check this site for the most current documentation, including important updates that may have been made after the release of the product.
Preface xiii Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Getting help The Hitachi Data Systems customer support staff is available 24 hours a day, seven days a week. If you need technical support, log on to the Hitachi Data Systems Support Portal for contact information:https:// portal.hds.com.
Comments Please send us your comments on this document: [email protected]. Include the document title, number, and revision, and refer to specific sections and paragraphs whenever possible. All comments become the property of Hitachi Data Systems. Thank you!
xiv Preface Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide 1
Overview of Copy-on-Write Snapshot
With Copy-on-Write Snapshot (SS), you can create virtual copies of a data volume in the Hitachi Virtual Storage Platform storage system. This chapter provides instructions for planning and designing, configuring, operating, monitoring, and troubleshooting SS.
□ Copy-on-Write Snapshot software
□ How Copy-on-Write Snapshot works
□ Components
□ Licenses and capacity
□ Consistency groups
□ Interfaces for performing Copy-on-Write Snapshot operations
□ Pair status
Overview of Copy-on-Write Snapshot 1–1 Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Copy-on-Write Snapshot software SS creates a virtual, point-in-time copy, or snapshot, of a data volume. Since only changed data blocks are stored in the SS storage pool, storage capacity is substantially less than the source volume. This results in significant savings compared with full cloning methods. The most probable types of target applications for SS are: • Database copies for decision support and database inquiries. • Non-disruptive backups from an SS secondary volume (S-VOL). • Periodic point-in-time disk copies for rapid restores in the event of a corrupted data volume.
How Copy-on-Write Snapshot works You create a volume pair when you complete the following: 1. Select the volume that you want to replicate. 2. Identify another volume that will contain the copy. 3. Associate the primary volume (P-VOL) and S-VOLs. 4. Set up a data pool. 5. Create the pair. The P-VOL is updated. The virtual volume (V-VOL) points to the point- in-time data in the P-VOL and data pool and mirrors it. The V-VOL contains a virtual copy of the P-VOL; it does not contain actual data. For more information about creating pairs, see Pair creation on page 5- 3. 6. Split the pair. The storage system continues to update the P-VOL. The V-VOL stops mirroring the current P-VOL. Instead, the V-VOL maintains a snapshot from the time of the split. For more information about splitting pairs, see Pair split on page 5-9. 7. Write data to the P-VOL. SS maintains the point-in-time image by copying the existing data to the data pool. 8. Resume the pair. The pool data is deleted.
Volume pairs: P-VOLs and V-VOLs A volume pair consists of a P-VOL, which contains the original and actual data, and at least one and up to 64 V-VOLs. The V-VOL is made up of pointers to the data in the P-VOL. The P-VOL and its V-VOLs are located in the same storage system. A V-VOL is also referred to as an S-VOL. Although you must set up V-VOLs with the same capacity as the paired P- VOL, the capacity is not actually used and remains available as free storage capacity. This V-VOL sizing requirement is necessary for SS and the storage
1–2 Overview of Copy-on-Write Snapshot Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide system logic. The V-VOL pointers to data in the data pool and P-VOL reside in cache memory. Enabling your system’s cache reserves part of your system’s cache for SS. Splitting the volume pair moves the original data to the data pool as the P- VOL is updated. The following figures show SS volumes and data pool interaction when you split the pair. The following figure shows how the V-VOL maintains the point-in-time data when you split the pair.
The following figure shows how the V-VOL maintains the point-in-time data when you split the pair.
The following image shows how the V-VOL maintains point-in-time data when you split the pair.
Overview of Copy-on-Write Snapshot 1–3 Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide Data pools When you replace data in the P-VOL, the data pool holds the data. After you split a pair, the V-VOL maintains pointers to point-in-time data. If updates are written to the P-VOL before you update the block, the data that is being replaced is first copied to the data pool. The V-VOL pointer to this block is updated to the new address in the data pool. All pairs sharing the same P- VOL use a data pool.
Components An SS system typically consists of the following components: •The SN • SS and ShadowImage (SI) software • Command Control Interface (CCI) • A pair of volumes (P-VOL and S-VOL) • A data pool • A consistency group
Licenses and capacity To use SS, SI must be installed on the same system. You must provide sufficient licensed capacity for both SS and SI. SS uses a V-VOL management area for managing V-VOLs and data pools. The V-VOL management area is created when additional shared memory is installed. The V-VOL management area consists of the following: • Pool management block • Pool association information
1–4 Overview of Copy-on-Write Snapshot Hitachi Virtual Storage Platform Hitachi Copy-on-Write Snapshot User Guide The following table shows the volumes and capacities for calculating the usable capacity for SS. The total applicable capacity must be less than the capacity you have licensed for SS. If you need more licensed capacity, call the Support Center.
Volumes to be added Applicable Normal VOL or Software Volume type capacity DP-VOL
SS P-VOL Normal VOL Volume capacity DP-VOL Pool capacity used by the volume Pool volume (pool- Normal VOL Volume capacity VOL)
Related topics • Calculating maximum SS pairs based on shared memory workflow on page 2-9.
Consistency groups Define SS pair operations in consistency groups to perform the operations on multiple pairs at the same time. Set up consistency groups during pair creation. For more information about creating pairs, see Pair creation on page 5-3.
Interfaces for performing Copy-on-Write Snapshot operations You perform setup and pair operations using a combination of the following: • The SN. For more information about the SN, see The Storage Navigator on page 1-5. • Command Control Interface (CCI). For more information about CCI, see Command Control Interface on page 1-6.
The Storage Navigator The Storage Navigator (SN) is connected to the Hitachi Virtual Storage Platform storage system through the TCP/IP local-area network (LAN). The SN communicates and exchanges data directly with the service processor (SVP) of the connected storage system. Use the SN to do the following: • Create the data pools and V-VOLs. For more information: