RAC Storage

Storage Options for RAC

  • CFS (Cluster File System) – Easy to manage but only available on some platforms.  Does not address striping and mirroring.
  • RAW – Available on all platforms but difficult to manage. Does not address striping and mirroring.
  • NFS – Easy to manage but only available on some platforms.  Does not address striping and mirroring.
  • ASM (Automatic Storage Management) – Easy to manage, available on ALL platforms, and DOES address striping and mirroring.

CFS (Cluster Filesystems)

  • The idea of CFS is to basically share file filesystems between nodes.
  • Easy to manage since you are dealing with regular files.
  • CFS is configured on shared storage.  Each node must have access to the storage in which the CFS is mounted.
  • NOT available on all platforms.  Supported CFS solutions currently:
  • OCFS on Linux and Windows (Oracle)
  • DBE/AC CFS (Veritas)
  • GPFS (AIX)
  • Tru64 CFS (HP Tru64)
  • Solaris QFS

RAW (character devices)

  • Hard to manage since you are dealing with character devices and not regular files.
  • Adding and resizing datafiles is not trivial.
  • On some operating systems volume groups need to deactivated before LVs can be manipulated or added.

NFS (Network Filesystem)

  • NOT available on all platforms.  Supported NFS solutions currently:
  • Network Appliance
  • Redhat Linux
  • Fujitsu Primecluster
  • Solaris Suncluster

ASM

  • Stripes files rather than logical volumes.
  • Enables online disk reconfiguration and dynamic rebalancing.
  • Provides adjustable re balancing speed.
  • Provides redundancy on a file basis.
  • Supports only Oracle files.
  • Is cluster aware.
  • Is automatically installed as part of the base code set .

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About the Author Atul Kumar

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5 comments
nettama says October 21, 2008

Thanks a lot for the info. But I believe ASM requires RAW file system. Pease clarify

Reply
Rupesh says October 22, 2008

As of oracle10.2x ASM is able to address the /dev/sd* directly and, you can directly map /dev/sd* devices. No need for raw devices. You just need to set the ASM_DISKSTRING parameter appropriately.

Reply
» RAC Basics : CRS, Voting Disk, OCR, Cache Fusion …. Online Apps DBA: One Stop Shop for Apps DBA’s says December 29, 2008

[…] solution for Oracle RAC like RAW device, OCFS, ASM… to know more about storage option in RAC click here . Interconnect – is private network that connects all the servers in cluster. Interconnect uses […]

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Ram says January 9, 2009

Hello Rupesh,

Does CFS means Oracle Cluster File System here? and do we get Oracle cluster Filesystem once we install Oracle Clusterware software?

Thank you
Ram

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Oracle RAC Basics | thatravinmaharaj says November 19, 2017

[…] solution for Oracle RAC like RAW device, OCFS, ASM… to know more about storage option in RAC click here . Interconnect – is private network that connects all the servers in cluster. Interconnect […]

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