Lsi Nytro Flash 101 May 2012


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What is Flash Memory? basic terms getting started what is wear leveling, what are the types of SSD, SLC, EMLC, MLC

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Lsi Nytro Flash 101 May 2012

  1. 1. LSI Channel SolutionsNytro SSD Flash 101 – Key TermsKent Abendroth - LSI Channel Manager 425-417-5245 – May 2012
  2. 2. What is Flash Memory?Solid state storage that is 100X to 1000X faster than hard drives yetprovides non-volatility. Feature/Benefit Limitations Remedies Applications needing • Higher $/GB than HDD • Wear leveling to low latency and high • Program-erase cycles ensure uniform wear IOPS. causes write wear and • Minimize writes limits write endurance2 LSI Confidential
  3. 3. Types of Flash Memory Technology Feature Limitations SLC (single level cell) Highest program-erase 100K program-erase cycles cycles 1 year data retention MLC (multiple level cell) 2X capacity of SLC 3K program-erase cycles 1 year data retention eMLC (enterprise MLC) High capacity and longer 30K program-erase cycles write life 3 months data retention Binary 01 00 10 00 01 10 10 01 Ascii H i SLC: 1 bit /cell MLC: 2 bits/cell3 LSI Confidential
  4. 4. Flash WritesWriting may require several steps:1. Moving existing data to provide space2. Erasing previously written data3. Writing new data Feature Benefit Limitations Over Provisioning - Supports high – until the reserved reserving unreported memory write rates memory has been used for immediate writes Garbage Collection - partially Necessary to meet Garbage collection may used blocks are combined to capacity limit write rates free blocks for new data specifications4 LSI Confidential
  5. 5. Writing Flash – No Overwrite Capability Binary Ascii 01001000 H Erase 11111111 Write 01101001 i Remaining writes: 2500 24995 LSI Confidential
  6. 6. Garbage Collection Before AfterLSI Nytro Value:Offloading garbage collection to LSI Flash controller ASICs less effect on applications.SandForce performs foreground garbage collection for higher write endurance.6 LSI Confidential
  7. 7. Wear Leveling Writes and erasures are evenly distributed across storage. All flash blocks experience the same amount of wear. Feature/Benefit Limitations Remedies Maximum endurance Increases flash Use dedicated flash enabled by ensuring management tasks management level write wear Nytro/SandForce Value Offloading management to dedicated SandForce controllers has less effect on applications. Advanced wear leveling algorithms further extend flash endurance.7 LSI Confidential
  8. 8. Write AmplificationEach write from an application may require several flash writes whichlowers endurance. Goal is to have amplification equal to 1. Nytro/SandForce Value Using data compression allows application to be less than 1. Write Cliff A sudden drop in write performance due to running out of reserved flash blocks Nytro/SandForce Value Foreground garbage collection mitigates a drop in performance8 LSI Confidential
  9. 9. LSI Storage Legacy – Innovation and Leadership Storage Systems Servers Network Attached PC SAS Storage Switch Network Switch Direct Attached LSI Silicon and Component Products Storage RAID Storage SAN HDD HBAs Software Adapter Controllers Silicon Silicon9 LSI Confidential LSI Confidential