HP XP Racks - Manual (Page 137)

SIMs and as SNMP traps to the open-systems host. See “Monitoring pool usage levels” (page 137)
for more information.
You can provision a larger virtual capacity beyond the pool capacity by using THP V-VOLs of Thin
Provisioning or Smart Tiers. However, when the pool’s free capacity is depleted, you can lose
access to THP V-VOLs that require more pool capacity. For example, if the pool usage rate is 100%
due to increased write operations, then I/O is not accepted and I/O will be stopped for a THP
V-VOL that failed to receive needed pool capacity. Therefore, you should carefully monitor the
pool usage or pool free capacity, as well as the level of provisioned virtual capacity.
Protecting data during pool shortages
To protect data from reading and writing to the THP V-VOL when the pool is full, you can apply
access attributes to a volume. To do this, you need to enable the use of the Data Retention, by
insuring the license is installed and using system option mode 729. This protection method applies
a Protect attribute to the THP V-VOL to protect volumes against write operations when the pool is
full. See
“Assigning an access attribute to a volume” (page 159) for more details.
The Protect attribute is applied to the THP V-VOL and is used in conjunction with other HP software
products. When the Protect attribute is applied to the THP V-VOL, Permitted appears in the S-VOL
field and 0 day appears in the Validation field of the Data Retention window. However, when the
Protect attribute is added to the THP V-VOL with the S-VOL unacceptable attribute available in Data
Retention, Not Permitted appears in the S-VOL field in the Data Retention window.
Monitoring pool usage levels
Several tools are available that show both the current pool usage rates and the changes over time
for those usage rates. These tools help you monitor the pool free space and estimate when you
will need to increase the pool capacity by adding pool volumes.
In Remote Web Console the Pool window, use the Virtual Volumes tab to view THP V-VOL usage
rates and pool usage rates (see
“Pools window” (page 309) and ( “Pools: Volume tabs” (page 314) .
In Remote Web Console, you can monitor THP V-VOL usage and pool usages rates using the
time-variable graph.
Monitoring performance
You can monitor system performance using Performance Monitor. For more information, see the
HP XP7 Performance for Open and Mainframe Systems User Guide.
You can monitor information on pools and THP V-VOLs using RAID Manager. For more information,
see the HP XP7 RAID Manager User Guide.
The following activities help you to monitor and control performance of the THP V-VOL. Collecting
monitor information and subsequent tuning may increase throughput and the operating rates.
•
Collecting monitor information. Collecting the following monitor information helps you determine
the pool load (including the access frequency, the trend of pool usage rates, and the access
load upon data drives) and THP V-VOL load (including the access frequency and the trend of
pool allocation rates). You can then use this monitor information to tune the appropriate
allocation.
◦ Access frequency of THP V-VOL, read hit rates, and write hit rates (using Performance
Monitor)
◦ Usage rates of property groups of pools (using Performance Monitor)
◦ Pool usage and elapsed time of pool usage (using Remote Web Console).
Monitoring capacity and performance 137