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Department of Electronics

Advanced Information Storage 18. Atsufumi Hirohata. Department of Electronics. 17:00 05/December/2013 Thursday (P/T 006). Quick Review over the Last Lecture. Millipede memory :. Nano-RAM :. Floating junction gate :. * http:// nanotechweb.org / cws /article/tech/36334;.

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Department of Electronics

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  1. Advanced Information Storage 18 Atsufumi Hirohata Department of Electronics 17:00 05/December/2013 Thursday (P/T 006)

  2. Quick Review over the Last Lecture Millipede memory : Nano-RAM : Floating junction gate : * http://nanotechweb.org/cws/article/tech/36334; * http://www.wikipedia.org/

  3. 18 RAID and Cloud Computing • Cloud computing • Storage technology • RAID • Parity error detection • Data striping • Data mirroring

  4. Cloud Computing In 2006, Eric E. Schmidt (Google) first introduced the phrase : * * http://www.wikipedia.org/

  5. Cloud Layers Cloud computing extends the existing concepts : * SaaS : Software as a service PaaS : Platform as a service IaaS : Infrastructure as a service * http://www.wikipedia.org/

  6. Cloud Companies * http://cloudtimes.org/2011/11/30/top-paas-saas-and-iaas-cloud-companies-by-cloudtimes/

  7. Cloud for Mobile Devices Mobile data are stored in servers in cloud : * 1 server in cloud Can store data from 120 iPhones 8 iPads * http://www.ubergizmo.com/2011/10/iphone-4s-review/

  8. Storage Technology In 1987, David Patterson, Garth A. Gibson and Randy Katz defined : * • Redundant array of inexpensive (independent) disks (RAID) • combines multiple disk drive components into a logic unit • Data distributed across the drives • Levels of redundancy and performance required • → RAID 0 ~ 10 * http://www.wikipedia.org/; ** http://bnrg.cs.berkeley.edu/~randy/

  9. RAID 0 Block-level striping without parity or mirroring : * • Minimum number of drives : 2 • Space efficiency : 1 • Fault tolerance : 0 • Array failure rate : 1 – (1 – r)n • Read performance : nX • Write performance : nX * http://www.wikipedia.org/

  10. Parity Error Detection Parity bit is used for error detection : * • Even / odd parity • Binary stream contains even / odd number of “1”. • For example, serial data transfer uses • Binary stream : 7 digit + Parity : 1 digit * http://www.computerhope.com/jargon/p/parity.htm

  11. Data Striping Data stream is distributed to several drives : * * http://www.ni.com/white-paper/6253/ja/

  12. RAID 1 Mirroring without parity or striping : * • Minimum number of drives : 2 • Space efficiency : 1 / n • Fault tolerance : n – 1 • Array failure rate : rn • Read performance : nX • Write performance : 1X * http://www.wikipedia.org/

  13. Data Mirroring Data are duplicated onto another drive(s) : * * http://www.openminds.co.uk/windows-solutions/data-replication/data-replicationmore-information.html

  14. RAID 2 Bit-level striping with dedicated Hamming code parity : * • Minimum number of drives : 3 • Space efficiency : 1 – 1 / n log 2 (n – 1) • Fault tolerance : 1 drive depending on the corresponding data and parity conditions • Array failure rate : variable • Read performance : variable • Write performance : variable * http://www.wikipedia.org/

  15. RAID 3 Bit-level striping with dedicated parity : * • Minimum number of drives : 3 • Space efficiency : 1 – 1 / n • Fault tolerance : 1 drive • Array failure rate : 1 – (1 – r) (n – 2) / 2 • Read performance : (n – 1 )X • Write performance : (n – 1 )X * http://www.wikipedia.org/

  16. RAID 4 Block-level striping with dedicated parity : * • Minimum number of drives : 3 • Space efficiency : 1 – 1 / n • Fault tolerance : 1 device • Array failure rate : 1 – (1 – r) (n – 2) / 2 • Read performance : (n – 1)X • Write performance : (n – 1)X * http://www.wikipedia.org/

  17. RAID 5 Block-level striping with dedicated parity : * • Minimum number of drives : 3 • Space efficiency : 1 – 1 / n • Fault tolerance : 1 device • Array failure rate : 1 – (1 – r) (n – 2) / 2 • Read performance : (n – 1)X • Write performance : (n – 1)X * http://www.wikipedia.org/

  18. RAID 6 Block-level striping with double-distributed parity : * • Minimum number of drives : 4 • Space efficiency : 1 – 2 / n • Fault tolerance : 2 device • Array failure rate : 1 – (1 – r) (n – 3) / 2 • Read performance : (n – 2)X • Write performance : (n – 2)X * http://www.wikipedia.org/

  19. RAID 10 Mirroring without parity and block-level striping : * • Minimum number of drives : 4 • Space efficiency : 2 / n • Fault tolerance : 1 device • Array failure rate : • Read performance : nX • Write performance : (n / 2)X * http://www.wikipedia.org/

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