Administrator Guide

Table Of Contents
Table 28. Historical performance (continued)
System component Graph Description
not cause any allocations. Pages are
allocated as data is written.
Tier Number of Page Moves In Number of pages moved into this tier
from a different tier.
Tier Number of Page Moves Out Number of pages moved out of this tier
to other tiers.
Tier Number of Page Rebalances Number of pages moved between disk
groups in this tier to automatically load
balance.
Tier Number of Initial Allocations Number of pages that are allocated as
a result of host writes. This number
does not include pages allocated as
a result of background tiering page
movement. (Tiering moves pages from
one tier to another, so one tier will
see a page deallocated, while another
tier will show pages allocated; these
background moves are not considered
initial allocations.)
Tier Number of Unmaps Number of 4-MB pages that are
automatically reclaimed and deallocated
because they are empty (they contain
only zeroes for data).
Tier Number of RFC Copies Number of 4-MB pages copied from
spinning disks to SSD read cache (read
flash cache).
Tier Number of Zero-Pages Reclaimed Number of empty (zero-filled) pages
that were reclaimed during this sample
period.
Updating historical statistics
The Performance topic can show historical performance statistics for the following types of components: disks, disk groups, and
virtual pools and tiers. By default, the newest 100 samples are shown. For more information about performance statistics, see
About performance statistics.
Update displayed historical statistics
1. Display a historical statistics graph as described in Viewing performance statistics.
2. Select Action > Update Historical Statistics.
The Update Historical Statistics panel opens and shows the default count value of 100.
3. To specify a count, in the Count field enter a value in the range of 5 to 100 and click OK.
4. To specify a time range, perform the following:
Select the Time Range check box.
Set date/time values for the starting and ending samples. The values must be between the current date/time and 6
months in the past. The ending values must be more recent than the starting values.
NOTE: If you specify a time range, it is recommended to specify a range of 24 hours or less.
Click OK.
In the Historical Data area of the Performance topic, the Time Range values are updated to show the times of the oldest and
newest samples displayed. The graph for the selected components is updated.
Working in the Performance topic
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