Receiving error "Exceeds maximum number of slabs supported" when creating a new VDO volume

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux 7.5
  • Red Hat Enterprise Linux 8
  • VDO Manager or LVM-VDO

Issue

  • When creating vdo on a 28 TB drive I am getting a slab error:

    vdo: ERROR - vdoformat: formatVDO failed on '/dev/mapper/vgVDO-lvVDO': VDO Status: Exceeds maximum number of slabs supported.

  • When trying to extend the vdo physical volume storage beyond 16TB with default slab size (of 2G), It logs below error:

    Dec 18 09:59:08 testbox kernel: kvdo0:dmsetup: mapToSystemError: mapping internal status code 2072 (kvdo: VDO_TOO_MANY_SLABS: kvdo: Exceeds maximum number of slabs supported) to EIO
Dec 18 09:59:08 testbox kernel: device-mapper: table: 253:6: vdo: Device prepareToGrowPhysical failed (specified physical size too big based on formatted slab size) (-EIO)

Resolution

  • The default slab size is 2GB, which can support up to 16TB of physical storage. You will need to set a larger slab size to account for the larger physical storage size. For example, you could use 8G slab size instead with the --vdoSlabSize=8G option.
  • One cannot change the slab size after vdo creation.
  • Please refer Slab size in VDO
  • Component
  • vdo

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