Viewing snapshot data capacity

Thin Image Advanced User Guide

Version
9.8.6
Audience
anonymous
Part Number
MK-98RD9033-00

You can use the raidcom get ldev command to view the snapshot data capacity for each P-VOL.

The snapshot data capacity indicates the pool capacity which is used as snapshot data written to the pool when data in the P-VOL and S-VOL is updated while the pair is split. The maximum total capacity of a P-VOL and its snapshot data capacity is 570 TB. Therefore, you cannot store data that exceeds this maximum capacity. You can judge depletion of capacity by checking the sum of the Used_Block(BLK) and Snap_Used_Pool(MB) values obtained by the raidcom get ldev command. The snapshot data capacity (Snap_Used_Pool(MB)) does not include the capacity of the control information for managing snapshot data and the capacity of the garbage data that remains after snapshot data is deleted. After snapshot data is deleted, it might take time until the snapshot data capacity decreases. This is because the processing of changing valid snapshot data to garbage data is performed asynchronously with the operation of deleting the snapshot data.

Although snapshot data is assigned from the pool in 42 MB blocks, data is written from the P-VOL and S-VOL in 8 KB blocks and compression and deduplication is applied to the data. Therefore, the snapshot data capacity before compression and deduplication is not always consistent with each pool's used capacity.

The following example shows how to use the raidcom get ldev command to view snapshot data capacity for the root volume in the Thin Image Advanced tree.

raidcom get ldev -ldev_id 0x2000
Serial# : 600023
LDEV : 8192
SL : 0
CL : 0
VOL_TYPE : OPEN-V-CVS
VOL_Capacity(BLK) : 33554432
NUM_PORT : 1
PORTs : CL3-A-0 1 3A-G00
F _POOLID : NONE
VOL_ATTR : CVS : QS : HDP : DRS
CMP : -
EXP_SPACE : -
B_POOLID : 60
LDEV_NAMING :
STS : NML
OPE_TYPE : NONE
OPE_RATE : 100
MP# : 0
SSID : 0024
Used_Block(BLK) : 0
FLA(MB) : Disable
RSV(MB) : 0
CSV_Status : ENABLED
CSV_PROGRESS(%) : -
CSV_Mode : COMPRESS
COMPRESSION_ACCELERATION : DISABLED
COMPRESSION_ACCELERATION_STATUS : DISABLED
CSV_PROCESS_MODE : INLINE
DEDUPLICATION_DATA : DISABLED
ALUA : Disable
RSGID : 0
PWSV_S : -
Snap_Used_Pool(MB) : 7018
CL_MIG : N
SNAP_USED(MB) : 0
SNAP_GARBAGE(MB) : -
DELETING_SNAP_GARBAGE : -
DELETING_SNAP_GARBAGE(%) : -
Used_Block(BLK)
Number of blocks used in the pool (including the number of blocks reserved by page reservation)
Snap_Used_Pool(MB)
Capacity used by snapshot data (excluding the control information and garbage)

For more information about the raidcom command, see the Command Control Interface Command Reference.