HP XP7 Storage - Manual (Page 74)

allocated during the monitoring cycle. Pages that are not allocated during performance
monitoring are not candidates for tier relocation.
•
Tier relocation can be performed concurrently on up to eight pools. If more than eight pools
are specified, relocation of the ninth pool starts after relocation of any of the first eight pools
has completed.
•
If Auto execution mode is specified, performance monitoring may stop about one minute
before to one minute after the beginning of the next monitor cycle start time.
•
The amount of relocation varies per cycle. In some cases, the cycle may end before all
relocation can be handled. If tier relocation doesn't finish completely within the cycle, relocation
to appropriate pages is executed in the next cycle.
•
Calculating the tier range values will be influenced by the capacity allocated to THP V-VOLs
with relocation disabled and the buffer reserve percentages.
•
While a pool-VOL is being deleted, tier relocation is not performed. After the pool-VOL deletion
is completed, tier relocation starts.
•
Frequency distribution is unavailable when there is no data provided by performance
monitoring.
•
While the frequency distribution graph is being created or the tier range values are being
calculated, the frequency distribution graph is not available. The time required for determining
the tier range values varies depending on the number of THP V-VOLs and total capacity. The
maximum time is about 20 minutes.
•
To balance the usage levels of all parity groups, rebalancing may be performed after several
tier relocation operations. If rebalancing is in progress, the next cycle of tier relocation might
be delayed.
For details on rebalancing, see “Rebalancing the usage level among parity groups” (page 99) .
The status of data collection, fixed monitoring, and tier relocation operations are described
in the following table. The latest fixed monitoring information is referenced when tiers are
relocated.
Solutions Tier relocation
operations Status of fixed
monitoring
information used in
tier relocation Status of data
collection in
progress Monitoring
information or
execution conditions
Unnecessary. After the
pages are allocated, Tiers of the pages
are not relocated. No monitoring
information on pages. Pages are not
monitored. Unallocated pages.
monitoring and
relocation are
performed
automatically.
Unnecessary. After the
pages are allocated, Tiers of the pages
are not relocated. Only monitoring
information on pages
is invalid. Monitoring on
pages is reset. Zero data is
discarded during
data monitoring.
monitoring and
relocation are
performed
automatically.
N/A If the tier relocation
setting is being Monitoring
information on the
volume is valid. Volume is
monitored. V-VOL settings do not
allow tier relocation.
disabled at the
performance
monitoring finish
time, tiers of the
volume are not
relocated.
74 Configuring thin provisioning