DSC861A Emerging Technology

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DSC861A Emerging Technology

• Storage Virtualization
• Team 3
• Jennifer Brola-Richards
• Mohib Fanek
• Kathy LarsonDonovan Miles Vishu Reddy
• Fran Trees

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Presentation Outline

• Storage Virtualization
• What is storage virtualization and why storage
  virtualization?
• Storage Evolution and Fundamental Concepts
• What are innovations and fundamental concepts
  associated with storage?
• Storage Virtualization Deep Dive
• What, Where and How of Storage Virtualization?
• Case Study
• Research Topics in Storage Virtualization
• What are potential topics of research and
  dissertation?
• Summary and Verbal Quiz

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What is storage virtualization?
Storage Virtualization is the next frontier in
Storage Advances that aims to provide a layer of
abstraction to reduce complexity. Storage
Networking Industry Association (SNIA) defines
Storage Virtualization as

1. The act of abstracting, hiding, or isolating the
   internal functions of a storage (sub) system or
   service from applications, host computers, or
   general network resources, for the purpose of
   enabling application and network-independent
   management of storage or data.
2. The application of virtualization to storage
   services or devices for the purpose of
   aggregating functions or devices, hiding
   complexity, or adding new capabilities to lower
   level storage resources.

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Why storage virtualization?
Storage Virtualization aims to provide a layer of
abstraction to manage storage and reduce
complexity !!!
Provided continuous availability despite
exponential growth (e.g. FaceBook- Over 55
billion page views a month, 41 million active
users1)
Effectively group and manage heterogeneous
storage devices servers (e.g. Estimated number
of Google Servers 450,000 2!)
Allocate and manage storage in accordance to the
Quality of Service (QoS) associated with the
data(e. g. Gartner estimates average data center
doubling its storage every 18 to 24 months)!)
Multiple Storage Software Platforms (e.g. IBM,
EMC, HP,..)
Mergers and Acquisitions (e.g. Microsoft Yahoo!)

1. Lucas Nealan, phpworks, Atlanta September 13,
   2007 (2) Wikipedia

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What are the innovations and fundamentals
associated with storage?
Client side storage innovations variety of
storage device innovations that are smaller,
higher capacity and cheaper have helped end
users cope with increasing storage requirements!
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What are the innovations and fundamentals
associated with storage?
Server side storage innovations a combination of
storage devices, storage interfaces and storage
software innovations have helped enterprises cope
with exponential growth of data storage
requirement !
Storage devices have evolved from tapes to hard
drives to RAID hard drives increasing capacity
and resiliency.
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What are the innovations and fundamentals
associated with storage?
Storage interface innovations have evolved from
SCSI to ISCI, Fiber Channel (FCP) and InfiniBand
to inter connect devices and transport the data
faster.
SCSI
FCP
ISCSI
Infiniband
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What are the innovations and fundamentals
associated with storage?
Storage Access File level access takes center
stage along with conventional Block level access.
Block level access Block addresses are used to
Read/Write data Read/Write, Block to the
storage media.
Sample conventional Block Allocation Map
File level access Files are accessed by
"semantics" instructions example Open, Close.
Data inside files is accessed by byte-ranges
within the file (example the first 10 bytes of a
file). GFS (Google File System) is an example of
a large scale distributed file system.
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What are the innovations and fundamentals
associated with storage?
Metadata is Data about data in the context of
storage metadata may describe an individual
datum, or content item, or a collection of data
including multiple content items. Examples
include file size, who created file, attributes
such as read only, free block bitmaps, control
data.
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What are the innovations and fundamentals
associated with storage?
Storage Software from simple back-up and restore
to advanced storage networks and storage
management software functions.
(A) Simple Direct Attached Storage (DAS)
(B) Storage Area Network (SAN)
(C) Network Attached Storage (NAS)
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What are the innovations and fundamentals
associated with storage?
SAN and NAS Key Differences
NAS SAN
Access Methods File access Disk block access
Access Medium Ethernet Fiber Channel
Architecture Decentralized Centralized
Transport Protocol Layer over TCP/IP SCSI/FC and SCSI/IP
Efficiency Less More
Sharing and Access Control Good Poor
Typical Applications Web Database
Typical Clients Workstations Database servers
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What and Where can Storage be Virtualized?
SNIA Storage Model
Potential Areas of Virtualization
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File Level Virtualization
2
Host Level Virtualization
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Network Virtualization

Block Virtualization
4

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Device Virtualization
1
Storage Level Virtualization
Source The Storage Networking Tutorials,
SNIAVIRT- Page 20 http//www.snia.org/education/
tutorials/
Host aka Server
Deviceaggregation of Host and Network (Meta
Data)
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What and Where can Storage be Virtualized?
Storage Virtualization Innovations and Trends
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2
1
5
3
6
Network Virtualization
Block Virtualization
Device Virtualization
File Level Virtualization
Storage Device Level Virtualization
Host Level Virtualization
Sub-Technique
Sub-Technique
Historical Mainframe Recent development example
NAS
Historical Mainframe Recent development example
VMware
Historical RAID Level, SCSI Interface Recent
Development Examples Fiber Channel
Major innovations continue to emerge even in
historical areas of storage virtualization
Symmetrical (aka in-band) and Asymmetrical (aka
Out-of-Band) are emerging as key areas of
abstraction and virtualization.
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How is storage virtualized at the enterprise
level?
Currently Networks are virtualized using Metadata
or Storage Volume Controllers. There are two
types of network virtualization
Metadata or Storage Volume Controllers are placed
(out of band) outside the path of data flow.
Metadata or Storage Volume Controllers (SVC) are
placed (in-band) or in the path of data flow.
Source IBM Redbook Page 8 http//www.redbooks.ibm
.com/redbooks/pdfs/sg246210.pdf
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How is storage virtualized at the enterprise
level?
In-Band Virtualization
2
SVC controls who can get access to the storage
device controls, how storage can be accessed, how
storage is allocated, etc.
1
Metadata or Storage Volume Controllers (SVC) are
placed (in-band) or in the path of data flow.
3
SVC are managed through Storage Management
Software.
Source IBM Redbook Page 10 http//www.redbooks.ib
m.com/redbooks/pdfs/sg246210.pdf
Key Challenge is the potential IO bottlenecks
4
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How is storage virtualized at the enterprise
level?
Out-of-Band Network Virtualization
2
Host sends Metadata to SVC
SVC controls who can get access to the storage
device controls, how storage can be accessed, how
storage is allocated, etc.
4
1
Metadata or Storage Volume Controllers (SVC) are
placed (in-band) or in the path of data flow.
3
Storage Pool sends Metadata to SVC
Source IBM Redbook Page 12 http//www.redbooks.ib
m.com/redbooks/pdfs/sg246210.pdf
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Virtualization Implementation Example
How is storage virtualized at enterprise level?
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Case Study

• The Study
• Shows that commingling of data and meta-data on a
  single logical device means that there is no way
  to achieve different service level objectives for
  data and meta-data in the same file system,
  without moving file-system specific knowledge
  into the logical disk layers.
• Shows that the standard assumptions underlying
  the organization of data and meta-data in file
  systems are no longer valid in virtualized
  storage environment and hence fail to materialize
  the full benefits of storage virtualization.
• Proposes a different file system organization of
  data and meta-data designed to exploit the power
  of virtualized storage.

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Case Study
Service Level requirements within a single file
system

• Organization A Needs No Encryption
• Organization B_ Needs Encryption
• Stores Medical Records
• Security requirements for file data is extremely
  high.
• Performs nightly indexing operation on file
  systems
• All directory information and file access times
  must be read to determine changed state of data
• Business requirement that all file data be
  encrypted at rest.
• File meta data has no security requirement

In Unix fast file system (ffs), a logical disk is
divided into collections of blocks called
cylinder groups, each of which stores both file
data blocks as well as file meta-data
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Case Study

• Results
• Clean logical separation between data and
  metadata
• Allows file system feature to use virtualization
  features and achieve different SLOs
• Redesign changes
• Code change
• Packing the re-located cylinder group header in
  the first few meta data cylinder groups ensures
  each header is located _at_ a fixed, predictable
  offset from the front of the block device
• User configurable block address space before
  which no data stored and after no meta data
  stored

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Case Study
5-7 gains on the new file system layout 31-44
for the file lookup and file delete benchmarks,
which result in little or no file data i/o, the
advantage of data-only encryption become obvious

• Future Work
• Differing SLOs for granular meta data
• Completely separate fixed/dynamic metadata
• Separate file data from user defined file
  attribute data
  

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Sample Research Topics in Storage Virtualization
What are potential topics of research and
dissertation?

• Bayesian analysis for resource management
• Bayesian analysis for diagnostics
• Trusted domains for security
• Storage Virtualization and Metadata Standards
• Algorithm advances for block, device and other
  component virtualization techniques

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Summary and Verbal Quiz

• Storage Basics
• What type of storage is found in your work
  station?
• What type of storage systems may be found in a
  large enterprise?
• How is data accessed from storage?
• Network Attached Storage (NAS) is well suited for
  what type of applications?
• Storage Area Network (SAN) is well suited for
  what type of applications?
• Storage Virtualization
• What is Storage Virtualization?
• Where and What can be virtualized in storage?
• How is storage virtualized at a network level?
• How is storage virtualization currently
  implemented?
• What are the potential research topics in storage
  virtualization?

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Annotated References

• Faibish. S., Fridella S, Bixby P., and Gupta U.,
  Storage Virtualization using a Block-device File
  System January 2008 ACM SIGOPS Operating
  Systems Review, Volume 42 Issue 1 Publisher
  ACM
• The Storage Networking Tutorials, SNIAVIRT
  http//www.snia.org/education/tutorials/
• http//en.wikipedia.org/wiki/Metadata
• http//www.redbooks.ibm.com/redbooks/pdfs/sg246210
  .pdf
• Nealan.L., phpworks, Atlanta September 13, 2007
• http//sizzo.org/wp/wp-content/uploads/2007/09/fa
  cebook_performance_caching.pdf
• 6. http//en.wikipedia.org/wiki/Google_platfo
  rm