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 .