Use the
Modify Copy Service Space panel in the SAN Volume Controller Console to
modify
the amount of memory that is available for Copy Services functions or
virtual disk (VDisk) mirroring.
Introduction
The total
bitmap space that is available for Copy Services
functions and VDisk mirroring in an I/O group is 512 MB.
Before
you specify the memory settings on this panel, consider the following
factors.
Each
1 MB of memory space enables the following capacities:
- 2
TB of total Metro Mirror and Global Mirror VDisk capacity when you
use
a grain size of 256 KB for the specified I/O group.
- 2 TB of
total FlashCopy® source VDisk capacity when you
use a
grain size of 256 KB for the specified I/O group.
- 512 GB
of total FlashCopy source VDisk capacity when you
use a
grain size of 64 KB for the specified I/O group.
- 1 TB of total
Incremental FlashCopy source VDisk capacity when
you use a grain size of 256 KB for the specified I/O group.
- 256
GB of total Incremental FlashCopy source VDisk capacity
when
you use a grain size of 64 KB for the specified I/O group.
- 2
TB of total VDisk mirroring capacity for
the specified I/O group.
- All 512 MB of memory
space enables 1 PB
of total VDisk mirroring capacity.
- For FlashCopy relationships,
only the source VDisk allocates space in the bitmap table.
- For
Metro Mirror or Global Mirror relationships, two bitmaps exist. One
is used for the master cluster and one is used for the auxiliary cluster
because
the direction of the relationship can be reversed.
- For multiple FlashCopy target VDisks, the number of
mappings
must be taken into account. For example, for a mapping with a 256
KB grain
size, 8 KB of memory allows one mapping between a 16 GB source VDisk
and a
16 GB target VDisk. This also allows two mappings between one 8 GB
source
VDisk and two 8 GB target VDisks.
- The smallest possible
bitmap is 4 KB; therefore a 512 byte VDisk requires
4 KB of bitmap space.
Attributes
The
following attributes are displayed in the table:
- Global/Metro
Mirror Total Memory
- Indicates the current setting of total
memory for Global Mirror and Metro
Mirror. Valid values can be between 0 - 512 MB.
- Global/Metro Mirror Free Memory
- Indicates
the current amount of free memory available to Global Mirror
and Metro Mirror feature. Valid values can be 0 - 512 MB.
- FlashCopy Total
Memory
- Indicates the current setting of total memory for FlashCopy feature. Valid values can
be 0 - 512 MB.
- FlashCopy Free
Memory
- Indicates the current amount of free memory
that is available
to FlashCopy feature.
Valid values can be 0 - 512 MB.
- VDisk
Mirroring Total Memory
- Indicates the current total
amount of memory allocated for VDisk
mirroring.
Valid values can be 0 - 512 MB.
- VDisk
Mirroring Free Memory
- Indicates
the current amount of memory which is free to use for VDisk
mirroring. Valid values can be 0 - 512 MB.
Fields
The
total bitmap space for Global / Metro Mirror,
FlashCopy,
and VDisk Mirroring cannot exceed 512 MB.
You can change the
following
fields:
- New Global / Metro Mirror Total Memory
(0 MB - 512 MB)
- Enter a value for the total amount of memory
to allocate for Global Mirror
and Metro Mirror feature. Valid values are 0 - 512 MB. You
can specify either MB or KB for the units; however, if you
select KB as the unit, the value must be divisible by 4. If kilobytes
are
specified, the valid range is 0 - 524288 KB.
- New FlashCopy Total
Memory (0 MB - 512 MB)
- Enter a value for the
total amount of memory to allocate
for FlashCopy feature.
Valid values are 0 - 512 MB. You can specify
either MB or KB for the units; however, if you select KB as the unit,
the
value must be divisible by 4. If kilobytes are specified, the valid
range
is 0 - 524288 KB.
- VDisk
Mirroring Total Memory (0 MB - 512 MB)
- Enter
a value for the total amount of memory that is allocated for VDisk
mirroring. Valid values are 0 - 512 MB.You
can specify either MB or KB for the units; however, if you select
KB as the
unit, the value must be divisible by 4. If kilobytes are specified,
the valid
range is 0 - 524288 KB.
Actions
The
following actions are available:
- OK
- Click
this button to change the Copy Services or
VDisk mirroring space allocations.
- Cancel
- Click this button to exit the panel without changing the Copy
Services or VDisk mirroring space allocations.