RAIN Technology for Reliable Data Storage

1. rain technology(redundant array of independent nodes) Presented by: Ravikrishnan.P

2. contents • RAID Flavors • RAID 0 • RAID 5 • rain architecture • Features of rain • rain platform • rainproject goals • Distributed storage • Advantages

3. INTRODUCTION • The name of the original research project is RAIN which stand’s for Reliable Array of Independent Nodes. The RAIN technology originated in a research project at the California Institute of Technology (Caltech),in collaboration with NASA’s Jet Propulsion Laboratory • A component that stores data across distributed processors and retrieves it even if some of the processors fail

4. RAID flavors • Commonly used ones: • RAID 0 • RAID 1 • RAID 5 • RAID 10 • Other types used…but rarely: RAID 2,3,4,6,50……

5. RAID 0

6. RAID 1 • RAID1 is ‘data mirroring’. • Two copies of the data are held on two physical disks, and the data is always identical.

7. RAID 5 “Distributed Parity” is the key word here.

8. Application MPI/PVM RAIN TCP/IP Ethernet Myrinet ATM Servernet Network Connections rain s/w architecture • Servernet:Error correction • ATM:aysnchronous transfer mode protocol • PVM:parallel virtual machine • MPI:message passing i/f

9. Application MPI/PVM RAIN TCP/IP Ethernet Myrinet ATM Servernet Network Connections • rain • Global state sharing protocol • Can use in different platform • Provide group communication • ip manage • Ip assign • Ip release Pool of ip

10. Myrinet NIC card Myrinet Switch:10Gb/s

11. Features of rain Bundled Interface Link Monitoring Fault Tolerant Interconnect Topology •  Communication •  Group Membership: Identifies healthy nodes that are participating in the cluster •  Data Storage

12. rain platform node node node Heterogeneous network of nodes and switches switch bus network switch node node node

13. Myrinet Switches 10 Pentium boxes w/multiple NICs Rain testbed

14. Proof of Concept: Video Server Video client & server on every node. C D B A switch switch

15. DATA STORED IN DISKS Insufficient storage to replicate all the data on each node. C D B A switch switch

16. Node Failure C D B A switch switch

17. Node Failure C D B A switch switch

18. Node Failure Dynamically switch to another node. C D B A switch switch

19. a b c d d+c d+a a+b b+c a b c d recover data b = a+b + a d = d+c + c k-of-n Code Erasure-correcting code: from any k of n columns

20. Link Failure C D B A switch switch

21. Link Failure C D B A switch switch

22. Link Failure Dynamically switch to another network path. C D B A switch switch

23. Switch Failure C D B A switch switch

24. Switch Failure C D B A switch switch

25. Switch Failure Dynamically switch to another network path. C D B A switch switch

26. Node Recovery C D B A switch switch

27. Node Recovery Continuous reconfiguration (e.g., load-balancing). C D B A switch switch

28. C C S S S C C S S C C How do you connect n nodes to a ring of n switches? S S S C C Fault-tolerant interconnect technologies • Goal • To connect computer nodes to a network of switches in order to maximize the network’s resistance to partitioning

29. N N S S S N N S S = Node N N N S S S = Switch N A ring of switches a naïve solution

30. N N S S S N N S S = Node N N N S S S = Switch N A ring of switches a naïve solution

31. A ring of switches N N S S S a naïve solution N N easily partitioned S S = Node N N N S S S = Switch N

32. 1 8 2 1 8 2 7 7 3 3 6 4 5 6 4 5 resistance to partitioning nodes on diagonals

33. 1 8 2 1 8 2 7 7 3 3 6 4 5 6 4 5 resistance to partitioning nodes on diagonals

34. 1 1 6 6 4 resistance to partitioning degree-2 compute nodes, degree-4 switches 8 2 8 2 nodes on diagonals 7 7 3 • tolerates any 3 switch failures (optimal) • generalizes to arbitrary node/switch degrees. 3 4 5 5

35. Point-to-Point Connectivity A node node node ? Is thepath from A to Bup or down? Network node node node B

36. connetivity Bi-directional communication. Linkis seen asupordownby each node. Node A Node B {U,D} {U,D} Each node sends out pings. A node may time-out, deciding the link is down.

37. B A C D group membership Consistent global view given local, point-to-point connectivity information ABCD ABCD • link/node failures • dynamic reconfiguration ABCD ABCD

38. B A D C group membership Token-Ring based Group Membership Protocol

39. 1: ABCD group membership Token-Ring based Group Membership Protocol B A Token carries: • group membership list • sequence number D C

40. 1: ABCD group membership Token-Ring based Group Membership Protocol B A 1 Token carries: • group membership list • sequence number D C

41. group membership Token-Ring based Group Membership Protocol B A 1 2 Token carries: • group membership list • sequence number 2: ABCD D C

42. group membership Token-Ring based Group Membership Protocol B A 1 2 Token carries: • group membership list • sequence number 3: ABCD D C 3

43. group membership Token-Ring based Group Membership Protocol B A 1 2 Token carries: • group membership list • sequence number 4: ABCD D C 4 3

44. group membership Token-Ring based Group Membership Protocol B A 5 2 Token carries: • group membership list • sequence number D C 4 3

45. group membership Node or link fails: B A 5 2 D C 4 3

46. group membership Node or link fails: B A 5 D C 4 3

47. group membership Node or link fails: ? B A 5 D C 4 3

48. group membership Node or link fails: ? B A 5 D C 4 3

49. 5: ACD group membership Node or link fails: B A 5 If a node is inaccessible, it is excluded and bypassed. D C 4 3

50. group membership Node or link fails: B A 5 If a node is inaccessible, it is excluded and bypassed. 6: ACD D C 4 6