IBM XIV Storage System Theory of Operation GA32-0639-03 IBM XIV Storage System Theory of Operation GA32-0639-03 Note: Before using this information and the product it supports, read the information in “Notices used in this document” on page v and “Notices” on page 105. Third Edition (August 2009) The following paragraph does not apply to any country (or region) where such provisions are inconsistent with local law. INTERNATIONAL BUSINESS MACHINES CORPORATION PROVIDES THIS PUBLICATION “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Some states (or regions) do not allow disclaimer of express or implied warranties in certain transactions; therefore, this statement may not apply to you. Order publications through your IBM representative or the IBM branch office serving your locality. © Copyright International Business Machines Corporation 2009. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Introduction .............v Chapter 5. Storage pools overview. 29 Purpose and scope ............v Document version ...........v Chapter 6. Thin provisioning .....31 Intended audience ...........v Related documentation ..........v Chapter 7. Target connectivity.....35 Notices used in this document .......v Defining a remote target object ........35 Document conventions..........vi Adding ports to remote target ........36 Terms and abbreviations .........vi Connecting between local and target ports ....36 Getting information, help, and service .....vi Symmetric connectivity for mirroring......38 How to send your comments ........vi Chapter 1. Overview: The IBM XIV Chapter 8. Synchronous remote Storage System ...........1 mirroring ..............39 Remote mirroring basic concepts .......39 Features and functionality ..........1 Remote mirroring operation .........40 Hardware overview ............1 Configuration options ...........41 Hardware components ..........1 Volume configuration ..........41 Supported interfaces ...........3 Communication errors..........42 Management options ..........4 Coupling activation...........42 Reliability ...............4 Synchronous mirroring statuses........43 Redundant components and no single point of Link status .............44 failure ...............5 Operational status ...........44 Data mirroring.............5 Synchronization status..........44 Self-healing mechanisms .........5 I/O operations .............46 Protected cache ............5 Synchronization process ..........46 Redundant power ...........5 State diagram.............47 Performance ..............6 Mandatory coupling ..........47 Total load balance ...........6 Best-effort coupling recovery .......48 Intelligent caching for improved performance . 6 Uncommitted data ...........48 Functionality ..............7 Constraints and limitations ........48 Upgradability .............8 Last-consistent snapshots .........48 Last consistent snapshot timestamp .....49 Chapter 2. Volumes and snapshots Secondary locked error status .......49 overview ..............9 Role switchover .............50 The volume life cycle ...........10 Role switchover when remote mirroring is Snapshots ...............11 operational ..............50 Redirect on write ...........11 Role switchover when remote mirroring is Auto-delete priority ..........12 nonoperational .............50 Snapshot name and association .......13 Switch secondary to primary .......51 The snapshot lifecycle ..........13 Secondary consistency ..........51 Switch primary to a secondary .......52 Chapter 3. Host System Attachment . 19 Resumption of remote mirroring after role change 52 Balanced traffic and no single point of failure . 19 Reconnection when both sides have the same role 53 Attaching volumes to hosts .........19 Miscellaneous .............53 Advanced host attachment .........19 Remote mirroring and consistency groups . 53 Clustering hosts into LUN maps .......20 Using remote mirroring for media error recovery 54 Volume mappings exceptions .......20 Supported configurations .........54 Host system attachment commands ......22 I/O performance versus synchronization speed optimization .............54 Chapter 4. Consistency groups Implications regarding other commands ....54 overview ..............25 Chapter 9. IP and Ethernet connectivity 57 Creating a consistency group ........25 Taking a snapshot of a consistency group ....25 Ethernet ports .............57 The snapshot group life cycle ........27 IP and Ethernet connectivity.........57 Restoring a consistency group ........28 Management connectivity .........60 © Copyright IBM Corp. 2009 iii Field technician ports ...........60 Glossary ..............89 Configuration guidelines summary ......61 Safety and environmental notices . 95 Chapter 10. Data migration ......63 Safety notices and labels ..........95 Data migration overview ..........63 Danger notices ............95 I/O handling in data migration........64 Labels ...............96 Data migration stages ...........65 Caution notices ............97 Handling failures ............66 Attention notices ...........97 Laser safety .............98 Chapter 11. Event handling ......67 Rack safety .............99 Event information ............67 Product recycling and disposal ......100 Viewing events .............68 Battery return program .........102 Defining events notification rules .......68 Fire suppression systems ........103 Alerting events configuration limitations . 69 Defining destinations ...........69 Notices ..............105 Defining gateways ............69 Notices ...............106 Copyrights ..............107 Chapter 12. Access control ......71 Trademarks ..............107 User roles and permission levels .......71 Electronic emission notices .........107 Predefined users.............72 Federal Communications Commission (FCC) Application administrator .........73 Class A Statement ...........108 User groups .............73 Industry Canada Class A Emission Compliance User group and host associations ......73 Statement .............108 Command conditions ..........74 Avis de conformité à la réglementation Authentication methods ..........75 d’Industrie Canada ..........108 Native authentication ..........75 European Union (EU) Electromagnetic LDAP-authentication ..........76 Compatibility Directive .........108 Switching between LDAP and native Australia and New Zealand Class A statement 109 authentication modes ..........78 Germany Electromagnetic Compatibility Logging and event reporting ........79 Directive ..............109 Command execution log .........79 People’s Republic of China Class A Electronic Object creation tracking .........79 Emission Statement ..........110 Event report destinations .........80 Taiwan Class A warning statement .....110 Access control commands .........80 Japan VCCI Class A ITE Electronic Emission Glossary of access control concepts ......81 Statement..............110 Korean Class A Electronic Emission Statement 110 Chapter 13. TPC interoperability ....83 Index ...............111 Chapter 14. Hot upgrade .......85 Chapter 15. Other features ......87 iv IBM XIV Storage System: Theory of Operation Introduction The IBM XIV Storage System is designed for secure, dependable, enterprise-grade data storage and access, straightforward installation and upgrading, and full scalability. The system contains proprietary and innovative algorithms that offset hardware malfunctions, minimize maintenance, and provide flexibility. The system uses off-the-shelf hardware components that are easy to integrate and support. Purpose and scope This document contains a complete hardware and software system overview of the IBM XIV Storage System. Relevant tables, charts, graphic interfaces, sample outputs, and appropriate examples are also provided. Document version This document supports version 10.1 of the IBM XIV Storage System code. Intended audience This document is a reference for administrators and IT staff that work with the IBM XIV Storage System. Related documentation The IBM XIV XCLI User Manual provides the commands used in the IBM XIV Command Line Interface (XCLI). This document can be obtained from the IBM XIV Storage System Information Center at http://publib.boulder.ibm.com/infocenter/ ibmxiv/r2/index.jsp by clicking IBM XIV Storage System → Product documentation in the left navigation pane. Notices used in this document The caution and danger statements used in this document also appear in the multilingual IBM Systems Safety Notices document. Each caution and danger statement is numbered for easy reference to the corresponding statements in the safety document. The following types of notices and statements are used in this document: Note These notices provide important tips, guidance, or advice. Important These notices provide information or advice that might help you avoid inconvenient or problem situations. Attention These notices indicate possible damage to programs, devices, or data. An attention notice is placed just before the instruction or situation in which damage could occur. Caution These statements indicate situations that can be potentially hazardous to © Copyright IBM Corp. 2009 v people because of some existing condition, or where a potentially dangerous situation might develop because of some unsafe practice. A caution statement is placed just before the description of a potentially hazardous procedure step or situation. Danger