03 infra TI Armazenamento Inteligente Components of intelligent storage system; List benefits of intelligent storage system; I/O Optimization; FrontEnd; Back-End; Explain intelligent cache algorithms and protection
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
Benefits of Intelligent Storage Increased capacity Improved performance Easier data management Improved data availability and protection Enhanced Business Continuity support Improved security and access control
Components of Storage System Intelligent Storage System Host Front End Connectivity FC SAN Back End Cache Physical Disks
Intelligent Storage System: Front End Intelligent Storage System Host Front End Connectivity Back End Cache FC SAN Ports Controllers Physical Disks
Front End Command Queuing A D C B A I/O Request s D C B A I/O Processing Order Front-End Controlle r D C B Cylinder s Without Optimization (FIFO) A D C B A I/O Request s D B C A I/O Processing Order Front-End Controlle r C B Cylinder s With command queuing D
Intelligent Storage System: Cache Intelligent Storage System Front End Host Back End Cache Connectivity FC SAN Physical Disks
Write Operation with Cache Write-through Cache Write Request Cachee Acknowledgemen t Write-back Write Request Acknowledgemen t Cachee Acknowledgement
Read with Cache: Hits and Misses Data found in cache = Hit Read Request Cache No data found = Miss Read Request Cache
Cache Management: Algorithms Least Recently Used (LRU) Discards least recently used data New Data Most Recently Used (MRU) Discards most recently used data Oldest Data
Cache Management: Watermarking 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 100 % HWM LWM Idle High watermark Forced
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
Intelligent Storage System: Back End Intelligent Storage System Host Front End Back End Cache Physical Disks Connectivity FC SAN Controllers Ports
Intelligent System: Physical Disks Intelligent Storage System Host Front End Connectivity FC SAN Back End Cache Physical Disks
What the Host Sees RAID Sets and LUNs Host 1 Intelligent Storage System Back End Front End LUN 0 Connectivity Cache Physical Disks LUN 0 FC SAN LUN 1 LUN 1 Host 2
LUN Masking Logical Unit Number 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
ISS: High-end Storage Systems Active-Active Configuration 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 Active Host Port Port Controll B e r Active Controll A e r Also referred as Active-active arrays I/O s are serviced through all the available path LUN Storage Array
Midrange Storage Systems Active Midrange array have two controllers, each with cache, Port RAID controllers and disks drive interfaces Host Designed for small and medium enterprises Less scalable as compared to high-end array Port Passiv e Controll B e r 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 Controll A e r Active-Passive Configuration LUN Storage Array
Discussão e exercícios Cite ao menos 2 mecanismos encontrados nos sistemas inteligentes de armazenamento. Explique os dois principais mecanismos de gerenciamento de cache encontrados nos sistemas inteligentes de armazenamento. Por que o Command Queue do Front End nos sistemas estudados têm sentido para o acesso a discos de estado sólido? Operações de READ e WRITE no cache apresentam que diferenças? Como você crê que podemos medir a eficiência do cache de um sistema inteligente de armazenamento. Por que não encontramos essa inteligência em sistemas de armazenamento interno local?
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