Using multipath storage devices

Depending on your environment, support for multipath storage devices might have some restrictions.

AIX®

Full support is available for SPIO and MPIO storage devices:
  • Harvested IBM.AgFileSystem resources can be automated.

    IBM.AgFileSystem resources are harvested if they are of type jfs or jfs2 and reside on storage entities that are harvested themselves (storage entities of class IBM.LogicalVolume, IBM.VolumeGroup, IBM.Disk).

  • User-defined IBM.AgFileSystem resources can be automated (for example, network file systems).
  • SCSI-2 reservation is supported for SPIO and MPIO storage devices using the Redundant Disk Array Controller (RDAC) driver.
Note: This driver is only available for the IBM® TotalStorage DS4k and DS6k families.
Limitations:
  • No striping
  • User-defined IBM.AgFileSystem resources can only be automated if the disk hosting the file system has the same device name on all nodes of the cluster.

Linux on POWER® and Linux on System x

Full support is available for single-path I/O (SPIO) storage devices, and for multipath storage I/O (MPIO) devices with Redundant Disk Array Controller (RDAC) device drivers, as well as md and device mapper provided devices.
  • Harvested IBM.AgFileSystem resources can be automated.

    IBM.AgFileSystem resources are harvested if they are of type ext2, ext3, or reiserfs and reside on storage entities that are themselves harvested (storage entities of class IBM.LogicalVolume, IBM.Partition, IBM.VolumeGroup, IBM.Disk.

  • User-defined IBM.AgFileSystem resources can be automated (for example, network file systems).
  • SCSI-2 reservation is supported for disks harvested from the RDAC driver.
  • Linux® RAID (/dev/device mapper provided or md devices) is supported.
  • Device mapper managed disks are supported.
Limitations:
  • File systems created on device mapper provided or md devices without using LVM are not harvested, they can only be automated using user-defined IBM.AgFileSystem resources.
  • device mapper provided or md devices themselves are only harvested as IBM.Disk resources if a physical volume has been created on the md device using the pvcreate command.
  • SCSI-2 reservation is not supported for non-RDAC drivers or for device mapper provided or md devices themselves.
  • User-defined IBM.AgFileSystem resources can only be automated if the disk hosting the file system has the same device name on all nodes of the cluster.
  • EVMS is not supported, which includes any Volume Groups/Logical Volumes created or managed by EVMS.
  • For SLES 12/15 and RHEL 7/8, harvesting of storage entities of class IBM.Disk, IBM.VolumeGroup, IBM.LogicalVolume, IBM.Partition, and IBM.AgFileSystem are supported. File systems may be automated if the limitations for device mapper provided or md devices listed above are met.

Linux on System z®

Device mapper provided or md devices are harvested as IBM.Disk resources if a physical volume has been created on the provided block device using the pvcreate command. This is independent of the underlying disk technology, ECKD or SCSI.

Limitations:
  • Only user-defined IBM.AgFileSystems resources or IBM.AgFileSystems resources residing on harvested device mapper provided or md devices can be automated. Resource harvesting for other disks is not supported. Even if harvesting of other disk resources is successful, the harvested resources cannot be automated.
  • User-defined IBM.AgFileSystems resources can only be automated if the disk hosting the file system has the same device name on all nodes of the cluster.
  • SCSI reservation is not supported.