Hitachi MK-96RD617-08 - Manual (Page 20)

2-4 About Performance Manager Options
Hitachi Universal Storage Platform V/VM Hitachi Performance Manager User’s Guide
Performance Management window can display the statistics within the
range of the storing periods above. You can specify a part of the storing period
to display the statistics on the lists and graphs of Performance Monitor.
All statistics, except some information related to Volume Migration, can be
displayed in short range (for the storing period corresponding to the setting for
the collecting interval) on Performance Management window. In addition,
usage statistics about resources in the storage system can be displayed in
both short range and long range because they are monitored in both ranges.
When you display usage statistics about resources, you can select the
displayed range.
For information on using Volume Migration, contact the Hitachi Data Systems
Support Center (see Calling the Hitachi Data Systems Support Center.
For more about statistics that can be monitored in short and long ranges, see
the description of Performance Management window in Performance
Monitor Window. For more about the relationship between collection interval
and the storing period of the statistics, see Monitoring Options Window.
Parity Group Usage Statistics
A parity group is a group of hard disk drives (HDDs) that form the basic unit of
storage for the USP V/VM storage system. All HDDs in a parity group must
have the same physical capacity. The USP V/VM supports three types of parity
groups as follows:
• RAID-1 parity group
A RAID-1 parity group consists of two pairs of HDDs in a mirrored
configuration.
• RAID-5 parity group
A RAID-5 parity group consists of four or eight HDDs. One of these HDDs is
used as a parity disk.
• RAID-6 parity group
A RAID-6 parity group consists of eight HDDs. Two of these HDDs are used
as a parity disk.
If the monitor data shows overall high parity group usage, you should consider
installing additional HDDs and using Volume Migration to migrate the high-
usage volumes to the new parity groups. If the monitor data shows that parity
group usage is not balanced, you can use Volume Migration to migrate
volumes from high-usage parity groups to low-usage parity groups.
For information on using Volume Migration, contact the Hitachi Data Systems
Support Center (see Calling the Hitachi Data Systems Support Center.
For details on how to view usage statistics about parity groups, see Viewing
Usage Statistics on Parity Groups.