HP XP20000XP24000 Disk Array - Manual (Page 23)

Figure 5 Managing Usage Rates and I/Os
By copying high-workload V-VOL data to low-workload pools using Business Copy, you can balance
the workload of pools.
Thresholds
XP Thin Provisioning monitors V-VOL and pool used capacity using thresholds. V-VOL capacity is
monitored using free space because V-VOL capacity is lower than pool capacity in general use. XP Thin
Provisioning monitors the pool used capacity in two phases. In the case of pool capacity, one of the
thresholds is a fixed value, which cannot be changed. Another threshold is a variable value, which can
be changed using the Change Pool Information dialog box. When the values go over or under the
threshold, XP Thin Provisioning outputs a SIM warning the users and reports trapping to SNMP. The
following describes the meaning of each threshold.
• V-VOL threshold
The V-VOL threshold is the ratio (%) of the free pool capacity to the free V-VOL capacity.
In the case that the free V-VOL capacity is 1 TB and the V-VOL threshold is 200%, when the free
pool capacity is lower than 2 TB (1 TB X 200% / 100%), XP Thin Provisioning warns users by
outputting a SIM and reports trapping to SNMP.
A pool is shared by several V-VOLs, so it is preferable that the pool capacity is larger than or
equal to a single free V-VOL capacity. Therefore, you can set the V-VOL threshold between 5%
and 300%. The default value is 5%.
• Pool threshold
The pool threshold is the ratio (%) of the used pool capacity to the total pool capacity. There are
two pool thresholds.
XP24000 Thin Provisioning Software User's Guide 23