This is normal behavior for XIV LUNs

In a thick pool space is dynamically allocated as needed, similar to a thin LUN. However, since there is enough space in the pool for all of the LUNs to be fully allocated you will never run into a situation where you run out of space in the pool. The advatages to running reclamation against a thick pool are as follows;

1) when there is disk/module failure, the data which needs to be rebuilt will reduce because of space reclamation
2) it can increase the spare capacity for rebuild

However, IBM support has confirmed that LUNs which are mirrored on the array or associated with an array-based snapshot do not support thin reclamation. If a snapshot or mirror is created on the array, then the customer should run "vxdctl enable" to rescan the current LUN attributes. The "thinrclm" flag should then disappear on the LUN in question. We detect whether or not the LUN supports reclamation by checking byte 5 of page 0xc0 of the SCSI inquiry.

0x00 is thick, while 0x01 is thin.

For example, both of these LUNs are part of the same pool, yet they have different values for byte 5 of page 0xc0;

# ./vxscsiinq -d -e 1 -p 192 /dev/rdsk/c3t500173804ECD0150d29s2

Inquiry for /dev/rdsk/c3t500173804ECD0150d29s2, evpd 0x1, page code 0xc0
/dev/rdsk/c3t500173804ECD0150d29s2: Raw data size 28
Bytes 0 - 9 0x00 0xc0 0x00 0x18 0x00 0x01 0x00 0x02 0x00 0x10
Bytes 10 - 19 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x80 0x00 0x00
Bytes 20 - 27 0x00 0x00 0x00 0x00 0x10 0x00 0x00 0x00

Vs

# ./vxscsiinq -d -e 1 -p 192 /dev/rdsk/c3t500173804ECD0140d3s2

Inquiry for /dev/rdsk/c3t500173804ECD0140d3s2, evpd 0x1, page code 0xc0
/dev/rdsk/c3t500173804ECD0140d3s2: Raw data size 28
Bytes 0 - 9 0x00 0xc0 0x00 0x18 0x00 0x00 0x00 0x02 0x00 0x10
Bytes 10 - 19 0x00 0x00 0x00 0x00 0x00 0x04 0x00 0x50 0x00 0x00
Bytes 20 - 27 0x00 0x00 0x00 0x00 0x10 0x00 0x00 0x00

The first example shows a LUN that supports reclamation, while the second example shows a LUN which does not. The difference is that the second LUN has a snapshot associated with it on the array. Therefore the bit changes to 0. Next time "vxdctl enable" is run the flags will be updated to reflect this.

Here is an example of how various types of XIV LUNs are expected to appear in VxVM

# vxdisk -e list

DEVICE       TYPE           DISK        GROUP        STATUS               OS_NATIVE_NAME   ATTR
disk_0       auto:none      -            -           online invalid       c0t0d0s2         -
disk_1       auto:none      -            -           online invalid       c0t1d0s2         -
xiv0_020a    auto:cdsdisk   xiv0_020a    thindg      online thinrclm      c3t50017380652B0142d1s2 tprclm RAID_10 <---- This LUN is part of a thin pool with no mirrors or snapshots
xiv0_0207    auto:cdsdisk   -            -           online               c3t50017380652B0150d4s2 std RAID_10 <---- This LUN is part of the same thin pool, and it has an associated snapshot on the array
xiv0_0208    auto:cdsdisk   xiv0_0208    thickdg     online thinrclm      c3t50017380652B0142d3s2 tprclm RAID_10 <---- This LUN is part of a thick pool with no mirrors or snapshots
xiv0_0209    auto:cdsdisk   -            -           online               c3t50017380652B0142d2s2 std RAID_10 <---- This LUN is part of a thick pool, and it has an associated snapshot on the array.
xiv0_524     auto:cdsdisk   -            -           online udid_mismatch c3t50017380652B0142d5s2 std snapshot optimized_snapshot <---- This is an array based snapshot of LUN xiv0_0209

Note that LUNs with associated snapshots do not have any flag to indicate this. They simply show up without the thinrclm flag. If the snapshot itself is presented from the array, then it will show up with a "snapshot" flag.

Applies To

IBM XIV array supporting thin reclamation

On IBM XIV arrays, LUNs can be provisioned in either thin or thick pools. XIV LUNs which are part of a thick pool may still show up with the "thinrclm" and "tprclm" flags in 'vxdisk list'. These "thick" LUNs fully support thin reclamation. Essentially they behave exactly the same as thin LUNs. The only time the "thinrclm" and "tprclm" flags will disappear is when the LUN is mirrored (on the array) or associated with an array-based snapshot. This is true for both "thick" and "thin" LUNs.