© 2009 EMC Corporation. All rights reserved. Intelligent Storage Systems Module 1.4

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 2 Module Objectives After completing this module, you will be able to:  Describe components of intelligent storage system  List benefits of intelligent storage system  Explain intelligent cache algorithms and protection  Describe intelligent storage array implementation – High-end storage array – Mid-range storage array

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 3 What is an Intelligent Storage System Intelligent Storage Systems are RAID arrays that are:  Highly optimized for I/O processing  Have large amounts of cache for improving I/O performance  Have operating environments that provide: – Intelligence for managing cache – Array resource allocation – Connectivity for heterogeneous hosts – Advanced array based local and remote replication options

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 4 Benefits of an Intelligent Storage System Intelligent storage system provides several benefits over a collection of disks in an array (JBOD) or even a RAID arrays: – Increased capacity – Improved performance – Easier data management – Improved data availability and protection – Enhanced Business Continuity support – Improved security and access control

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 5 Components of an Intelligent Storage System Host Connectivity FC SAN Front EndBack End Cache Physical Disks Intelligent Storage System

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 6 Intelligent Storage System: Front End Host Connectivity Front EndBack End Cache Physical Disks Intelligent Storage System FC SAN Ports Controllers

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 7 Front End Command Queuing DCBA DCBA A B C D I/O RequestsI/O Processing Order Front-End Controller Cylinders Without Optimization (FIFO) DBCADCBA A B C D I/O RequestsI/O Processing Order Front-End Controller Cylinders With command queuing

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 8 Intelligent Storage System: Cache Host Connectivity Front EndBack End Cache Physical Disks Intelligent Storage System FC SAN

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 9 Write Request Write Operation with Cache Write Request Write-through Cache Write-back Acknowledgement Cache Acknowledgement

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 10 Read Request Cache Read Request Cache Data found in cache = ‘Hit’ No data found = ‘Miss’ Read Operation with Cache: ‘Hits’ and ‘Misses’

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 11 Cache Management: Algorithms  Least Recently Used (LRU) – Discards least recently used data  Most Recently Used (MRU) – Discards most recently used data New Data Oldest Data

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 12 Cache Management: Watermarking LWM HWM 100 % Idle flushing High watermark flushingForced flushing  Manage peak I/O requests “bursts” through flushing/de- staging – Idle flushing, High Watermark flushing and Forced flushing  For maximum performance: – Provide headroom in write cache for I/O bursts

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 13 Cache Data Protection  Protecting cache data against failure: – Cache mirroring  Each write to the cache is held in two different memory locations on two independent memory cards – Cache vaulting  Cache is exposed to the risk of uncommitted data loss due to power failure

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 14 Intelligent Storage System: Back End Host Connectivity PortsControllers Front EndBack End Cache Physical Disks Intelligent Storage System FC SAN

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 15 Intelligent Storage System: Physical Disks Host Connectivity Front EndBack End Cache Physical Disks Intelligent Storage System FC SAN

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 16 What the Host Sees – RAID Sets and LUNs Host 1 Host 2 LUN 0 LUN 1 Front EndBack End Cache Physical Disks Intelligent Storage System LUN 0 LUN 1 Connectivity FC SAN

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 17 LUN Masking  LUN masking is access control mechanism  Process of masking LUNs from unauthorized access  Implemented on storage arrays  Storage group logical entity that contains one or more LUNs and one host

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 18 ISS Implementation: High-end Storage Systems  Also referred as Active-active arrays – I/O’s are serviced through all the available path  Following are high-end array capabilities: – Large storage capacity – Huge cache to service host I/Os – Fault tolerance architecture – Multiple front-end ports and support to interface protocols – High scalability – Ability to handle large amounts of concurrent I/Os  Designed for large enterprises Host Storage Array Active-Active Configuration Active LUN Controller A Controller B Port

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 19 Midrange Storage Systems  Also referred as Active-passive arrays – Host can perform I/Os to LUNs only through active paths – Other paths remain passive till active path fails  Midrange array have two controllers, each with cache, RAID controllers and disks drive interfaces  Designed for small and medium enterprises  Less scalable as compared to high-end array Host Storage Array Active-Passive Configuration Active Passive LUN Controller A Controller B Port

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 20 Module Summary Key points covered in this module:  Intelligent Storage Systems features  Components of Intelligent Storage Systems  Cache management algorithms  Intelligent Storage System implementation – High-end storage array – Mid range storage array

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 21 Concept in Practice: EMC CLARiiON  Support for UltraFlex technology  Scalable from up to 960 disks  Supports flash drives  Supports different types and sizes of drives, and RAID types (0, 1, 1+0, 3, 5, 6)  Supports up to 16 GB of available cache memory per controller (Storage Processor)  Enhances availability with non disruptive upgrade and failover  Ensures data protection through mirrored write cache and cache vaulting  Supports storage-based local and remote data replication – Through SnapView and MirrorView software

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 22 CLARiiON CX-4 Architecture

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 23 EMC Symmetrix  Incrementally scalable to 2,400 disks  Supports Flash-based solid-state drives  Dynamic global cache memory (16 GB– 512 GB)  Advanced processing power (up to 130 PowerPC)  Direct matrix Architecture  High data processing bandwidth (up to 128 GB/s)  Data protection with RAID 1, 1+0 (also known as 10 for mainframe), 5, and 6  Storage-based local and remote replication – Through TimeFinder and SRDF software

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 24 Direct Matrix Architecture

© 2009 EMC Corporation. All rights reserved. Intelligent Storage System - 25 Check Your Knowledge  What are the parts of an Intelligent Storage System?  What are the differences between a high-end and midrange storage array?  What is the difference between a read cache hit and a read cache miss?  What is the difference between Least Recently Used and Most Recently Used algorithms?  What is the difference between Write-through and Write- back cache?