1. Storage Virtualization Seminar Stephen Foskett Director of Data Practice, Contoural

2. Part 1:Breaking the Connections Storage virtualization is here, breaking the connection between physical storage infrastructure and the logical way we use it

3. Agenda What is storage virtualization? Volume management Advanced file systems Virtualizing the SAN Virtual NAS

5. …but your storage is already virtualized!

6. Disk drives map blocks

7. RAID is as old as storage (conceived 1978-1988)

8. Modern OSes include volume management and path management

9. Network-attached storage (NAS) redirectors and DFS

10. Storage arrays are highly virtualized (clustering, LUN carving, relocation, tiering, etc…)

12. What and Why? Virtualization removes the hard connection between storage hardware and users Address space is mapped to logical rather than physical locations The virtualizing service consistently maintains this meta-data I/O can be redirected to a new physical location We gain by virtualizing Efficiency, flexibility, and scalability Stability, availability, and recoverability

14. Virtualization exists for both block and file storage networks

15. Can be located in server-based software, on network-based appliances, SAN switches, or integrated with the storage arraySwitch Appliance Array

17. Volume managers abstract block storage (LUNs, disks, partitions) into virtual “volumes”

18. Very common – all* modern OSes have volume managers built in

19. Windows Logical Disk Manager, Linux LVM/EVMS, AIX LVM, HP-UX LVM, Solaris Solstice, Veritas Volume Manager

20. Mostly used for flexibility

21. Resize volumes

22. Protect data (RAID)

23. Add capacity (concatenate or expand stripe or RAID)

24. Mirror, snapshot, replicate

27. Open source (CDDL) project managed by Sun

28. Will probably replace UFS (Sun), HFS+ (Apple OS X Snow Leopard Server)

29. ZFS creates a truly flexible, extensible, and full-featured pool of storage across systems and disks

30. Filesystems contained in “zpools” on “vdevs” with striping and optional RAID-Z/Z2

31. 128-bit addresses mean near-infinite capacity (in theory)

32. Blocks are “copy-on-write” with checksums for snapshots, clones, authentication

33. …but there are some limitations

34. Adding (and especially removing) vdevs is hard/impossible

35. Stacked RAID is impossible

38. Can require less reconfiguration and server work

39. Works with all servers and storage (potentially)

40. Resides on appliance or switch placed in the storage network

41. Some are in the data path, others are less so

42. Brocade and Cisco switches have application blades

44. SAN Virtualization Products

46. IP network connectivity and host processing possibilities

47. Multitude of file servers? Virtualize!

48. Global namespace across all NAS and servers

49. Share excess capacity

50. Transparently migrate data (easier than redirecting users!)

51. Tier files on large “shares” with variety of data

54. Arrays create large RAID sets and “carve out” virtual LUNs for use by servers

55. Controller clusters (and grids) redirect activity based on workload and availability

56. Snapshots/mirrors and replication are common features

57. A new generation arrays with virtualization features is appearing, with tiered storage, thin provisioning, migration, de-duplication

59. Most arrays support multiple drive types

60. “Bulk” SATA or SAS drives are common (500 GB - 1 TB)

61. Solid-state drives are the latest innovation

62. Some arrays can dynamically load balance

63. A few can “hide” other arrays “behind”

64. SAN: HDS USP-V and similar from Sun, HP

66. Some arrays can “thinly” provision just the capacity that actually contains data

67. 500 GB request for new project, but only 2 GB of initial data is written – array only allocates 2 GB and expands as data is written

68. Symantec API, thin-unprovisioning capabilities

69. What’s not to love?

70. Oops – we provisioned a petabyte and ran out of storage

71. Chunk sizes and formatting conflicts

72. Can it thin unprovision?

73. Can it replicate to and from thin provisioned volumes?

75. More appropriate to some applications than others

76. Software or appliance (and now array!) analyzes files or blocks, saving duplicates just once

77. Block-based reduce capacity more by looking inside files

78. Once common only for archives, now available for production data

79. Serious implications for performance and capacity utilization

80. In-line devices process all data before it is written

82. The Next-Generation Data Center Virtualization of server and storage will transform the data center Clusters of capability host virtual servers Cradle to grave integrated management SAN/network convergence is next InfiniBand offers converged virtual connectivity today iSCSI and FCoE become datacenter Ethernet (DCE) with converged network adapters (CNAs)

83. Audience Response Question?

84. Break sponsored by

85. Part 2:Storage in the Virtual World Responding to the demands of server, application, and business users with new flexible technologies

86. Agenda Why virtual storage for virtual servers? The real world impact and benefits Best practices for implementation

87. Poll: Who Is Using VMware?

88. Poll: Does Server Virtualization Improve Storage Utilization?

89. Why Use Virtual Storage For Virtual Servers? Mobility of virtual machines between physical servers for load balancing Improved disaster recovery Higher availability Enabling physical server upgrades Operational recovery of virtual machine images

91. VMware is the #1 driver of SAN adoption today!

92. 60% of virtual server storage is on SAN or NAS (ESG 2008)

93. 86% have implemented some server virtualization (ESG 2008)

96. Patchwork of support, few standards

97. “VMware mode” on storage arrays

98. Virtual HBA/N_Port ID Virtualization (NPIV)

99. Everyone is qualifying everyone and jockeying for position

100. Can be “detrimental” to storage utilization

102. VMware Storage Options:Shared Storage on NFS Shared storage on NFS – skip VMFS and use NAS NTFS is the datastore Wow! Simple – no SAN Multiple queues Flexible (on-the-fly changes) Simple snap and replicate* Enables full Vmotion Use fixed LACP for trunking But… Less familiar (3.0+) CPU load questions Default limited to 8 NFS datastores Will multi-VMDK snaps be consistent? VM Host Guest OS NFS Storage VMDK

103. VMware Storage Options:Raw Device Mapping (RDM) Raw device mapping (RDM) - guest VM’s access storage directly over iSCSI or FC VM’s can even boot from raw devices Hyper-V pass-through LUN is similar Great! Per-server queues for performance Easier measurement The only method for clustering But… Tricky VMotion and DRS No storage VMotion More management overhead Limited to 256 LUNs per data center VM Host Guest OS I/O Mapping File SAN Storage

104. Physical vs. Virtual RDM Virtual Compatibility Mode Appears the same as a VMDK on VMFS Retains file locking for clustering Allows VM snapshots, clones, VMotion Retains same characteristics if storage is moved Physical Compatibility Mode Appears as a LUN on a “hard” host Allows V-to-P clustering,a VMware locking No VM snapshots, VCB, VMotion All characteristics and SCSI commands (except “Report LUN”) are passed through – required for some SAN management software

105. Physical vs. Virtual RDM

106. Poll: Which VMware Storage Method Performs Best? Mixed Random I/O CPU Cost Per I/O VMFS, RDM (p), or RDM (v) Source: “Performance Characterization of VMFS and RDM Using a SAN”, VMware Inc., 2008

107. Which Storage Protocol is For You? FC, iSCSI, NFS all work well Most production VM data is on FC Either/or? - 50% use a combination (ESG 2008) Leverage what you have and are familiar with For IP storage Use TOE cards/iSCSI HBAs Use a separate network or VLAN Is your switch backplane fast? No VM Cluster support with iSCSI* For FC storage 4 Gb FC is awesome for VM’s Get NPIV (if you can)

108. Poll: Which Storage Protocol Performs Best? Throughput by I/O Size CPU Cost Per I/O Fibre Channel, NFS, iSCSI (sw), iSCSI (TOE) Source: “Comparison of Storage Protocol Performance”, VMware Inc., 2008

109. Storage Configuration Best Practices Separate operating system and application data OS volumes (C: or /) on a different VMFS or LUN from applications (D: etc) Heavy apps get their own VMFS or raw LUN(s) Optimize storage by application Consider different tiers or RAID levels for OS, data, transaction logs - automated tiering can help No more than one VMFS per LUN Less than 16 production ESX .VMDKs per VMFS Get thin Deduplication can have a huge impact on VMDKs created from a template! Thin provisioning can be very useful – Thin disk is in Server, not ESX!?!

110. Why NPIV Matters Without NPIV N_Port ID Virtualization (NPIV) gives each server a unique WWN Easier to move and clone* virtual servers Better handling of fabric login Virtual servers can have their own LUNs, QoS, and zoning Just like a real server! When looking at NPIV, consider: How many virtual WWNs does it support? T11 spec says “up to 256” OS, virtualization software, HBA, FC switch, and array support and licensing Can’t upgrade some old hardware for NPIV, especially HBAs Virtual Server Virtual Server Virtual Server 21:00:00:e0:8b:05:05:04 With NPIV Virtual Server Virtual Server Virtual Server …05:05:05 …05:05:06 …05:05:07

111. Virtualization-Enabled Disaster Recovery DR is a prime beneficiary of server and storage virtualization Fewer remote machines idling No need for identical equipment Quicker recovery (RTO) through preparation and automation Who’s doing it? 26% are replicating server images, an additional 39% plan to (ESG 2008) Half have never used replication before (ESG 2008) News: VMware Site Recovery Manager (SRM) integrates storage replication with DR

112. Enhancing Virtual Servers with Storage Virtualization Mobility of server and storage images enhances load balancing, availability, and maintenance SAN and NAS arrays can snap and replicate server images VMotion moves the server, Storage VMotion (new in 3.5) moves the storage between shared storage locations Virtualization-optimized storage Pillar and HDS claim to tweak allocation per VM Many vendors announcing compatibility with VMware SRM Most new arrays are NPIV-capable Virtual storage appliances LeftHand VSA – A virtual virtualized storage array FalconStor CDP – a virtual CDP system

113. Enabling Virtual Backup Virtual servers cause havoc for traditional client/server backups I/O crunch as schedules kick off – load is consolidated instead of balanced Difficult to manage and administer (or even comprehend!) Storage virtualization can help Add disk to handle the load (VTL) Switch to alternative mechanisms (snapshots, CDP) Consider VMware consolidated backup (VCB) Snapshot-based backup of shared VMware storage Block-based backup of all VMDKs on a physical server

114. Audience Response Question?

115. Break sponsored by

116. Part 3:Should You Virtualize? A look at the practical benefits of virtualized storage

118. Performance

119. Stability, availability, and recoverability

120. The down side

121. Cost benefit analysis

123. The right amount of storage for the application

124. The right type (tiered storage)

125. Quickly add and remove on demand

126. Move storage from device to another

127. Tiering, expansion, retirement

129. Performance A battle royale between in- and out-of-band! In-band virtualization can improve performance with caching Out-of-band stays out of the way, relying on caching at the device level Split-path adds scalability to in-band Large arrays perform better (usually) than lots of tiny RAIDs or disks First rule of performance: Spindles Second rule of performance: Cache Third rule of performance: I/O Bottlenecks

130. Solid State Drives (and Myths) The new (old) buzz RAM vs. NAND flash vs. disk EMC added flash drives to the DMX (CX?) as “tier-0”, CEO Joe Tucci claims flash will displace high-end disk after 2010 Sun, HP adding flash to the server as a cache Gear6 caches NAS with RAM But… Are they reliable? Do they really perform that well? Will you be able to use them? Is the 10x-30x cost justified? Do they really save power? Notes: 1 – No one writes this fast 24x7 2 – Manufacturers claim 2x to 10x better endurance

131. Stability, Availability, and Recoverability Replication creates copies of storage in other locations Local replicas (mirrors and snapshots) are usually frequent and focused on restoring data in daily use Remote replicas are used to recover from disasters Virtualization can ease replication Single point of configuration and monitoring Can support different hardware at each location

132. We Love It! Efficiency, scalability, performance, availability, recoverability, etc… Without virtualization, none of this can happen!

134. Downtime and performance affect more systems

135. Harder to back out if unsatisfied

136. Additional complexity and interoperability concerns

138. Cost Benefit Analysis Benefits Improved utilization Tiering lowers per-GB cost Reduced need for proprietary technologies Potential reduction of administrative/ staffing costs Flexibility boosts IT response time Performance boosts operational efficiency Costs Additional hardware and software cost Added complexity, vendors Training and daily management Reporting and incomprehensibility Possible negative performance impact Stability and reliability concerns

139. Where Will You Virtualize?

140. Closing Thought:What Is Virtualization Good For? Virtualization is a technology not a product What will you get from using it? Better DR? Improved service levels and availability? Better performance? Shortened provisioning time? The cost must be justified based on business benefit, not cool technology

141. Audience Response Questions? Stephen Foskett Contoural, Inc. sfoskett@contoural.com http://blog.fosketts.net