Object Store Over Network

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Object Store Over Network

• Po-Chun Liu
• Adviser Pro. Yarsun Hsu

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Outline

• What is object store ?
• Why object store ?
• Storage over TCP/IP network iSCSI
• IBM prototypes for object store
• On going work
• References

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What is Object Store ?

• A collection of objects
• Object can be a file, a data base, or even a
  logic partition
• Users operation
• Create an object, read/write at a logical
  location in the object, delete an object
• All operations carry a credential
• Different access rights for different portions of
  a volume

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What is Object Store ?
5
What is Object Store ?
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Why Object store ?

• Using block storage raises three main issues in
  Storage Area Network (SAN)
• Security
• Scalability
• Management

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Security in SAN

• If a host has the right to access a volume, it
  has complete access to all of the data on the
  volume
• Provide all or nothing access to a LU for a host
• Solution in block store
• The control unit needs to know which blocks have
  the same security attributes, ex., belong to the
  same file
• Not practical because there are too many actively
  used blocks for a file

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Security in SAN

• Solution in object store
• A file is an object and has its own access right
• A volume consists of objects with different
  access right
• Thus a host which can access some objects in a
  volume may not have the right to access other
  objects in the volume

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Scalability in SAN

• Scalability is not typically an issue unless
  hosts share access to volumes
• Shared access requires coordination, which leads
  to scalability problems
• File systems must coordinate allocation of blocks
  to files
• Shared read-write access hosts must coordinate
  usage of data blocks with other hosts
• Additional communication between hosts and
  metadata server and metadata servers is needed
• Object store handles the space allocation
• No additional communication is needed between
  nodes

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Management in SAN

• We would like to support functions such as QoS
  for individual files
• Block control unit only recognizes blocks and
  logic units
• Much like the issue that arises in security
• Management at block level is not practical
• Object can contain attributes for individual files

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Storage Over IP Network - iSCSI
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How iSCSI Works ?

• Built on SCSI and Ethernet
• Encapsulate SCSI command and data into PDU
• When connected, the target is accessed as local
  SCSI device
• Three types of initiators

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Benefits of iSCSI

• Cost-effective solution for SAN
• By consolidating storage, cross platform sharing
  is much easier
• With the development of Gigabit Ethernet, iSCSI
  can provide performance comparable to Fiber
  Cannel
• Advances in 10 Gb Ethernet make iSCSI superior to
  any other storage solution

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IBM OSD iSCSI Initiator

• Built on top of the Linux SCSI stack
• Generic T10 OSD component
• Construct and parse OSD SCSI commands according
  to the T10 standard
• Independent of SCSI transport
• iSCSI component
• Transport SCSI command over IP network

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On Going Work

• Simulate object store on existing iSCSI storage
  device

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References

• M. Factor, K. Meth, D. Naor, O. Rodeh, and J.
  Satran, "Object Storage The Future Building
  Block for Storage Systems." A position paper on
  Object Storage. In proceedings of the Second
  International IEEE Symposium on Emergence of
  Globally Distributed Data, June 19-24, 2005,
  Sardinia, Italy.
• A. Azagury, V. Dreizin, M. Factor, E. Henis, D.
  Naor, N. Rinetzky, O. Rodeh, J. Satran, A.
  Tavory, and L. Yerushalmi. "Towards an Object
  Store." In the 20th IEEE Symposium on Mass
  Storage Systems, 2003.
• Equallogic, Inc. iSCSI The New Standard for
  Networked Storage., 2003
• IBM Haifa Labs, http//www.haifa.il.ibm.com/projec
  ts/storage/objectstore/index.html