IBM DS8800, Introduction And Planning Manual, Page: 64 / 256

Dynamic volume expansion
The DS8000 series supports dynamic volume expansion.
Dynamic volume expansion increases the capacity of open systems and System z
volumes, while the volume remains connected to a host system. This capability
simplifies data growth by providing volume expansion without taking volumes
offline.
Since some operating systems do not support a change in volume size, a host
action is required to detect the change after the volume capacity is increased.
The following maximum volume sizes are supported:
v
Open Systems FB volumes - 16 TB
v System z CKD volume types 3390 model 9, and custom is 65520 cylinders
v
System z CKD volume type 3390 model 3 is 3339 cylinders
v System z CKD volume types 3390 model A, up to 1,182,006 cylinders
Count key data and fixed block volume deletion prevention
The DS CLI and DS Storage Manager have been enhanced to include a force option
that is designed to prevent deleting count key data (CKD) and fixed block (FB)
volumes that are in use or online.
If the force option is enabled, the DS8000 checks whether the volumes are online or
in use before they are deleted. (For CKD volumes, a volume is online if it is
participating in a Copy Services relationship or if it is online to a System z host.
For FB volumes, a volume is online if it is participating in a Copy Services
relationship or is part of a volume group.) If you specify the force option when
you delete a volume, online checking is suppressed and the DS8000 deletes the
volume regardless if it is online or in use.
IBM System Storage Easy Tier
Easy Tier is an optional, no charge feature on the DS8800 and the DS8700. It offers
enhanced capabilities such as manual volume capacity rebalance, auto performance
rebalancing in both homogenous and hybrid pools, hot spot management, rank
depopulation, manual volume migration, and thin provisioning support (ESE
volumes only) for Easy Tier features. Easy Tier determines the appropriate tier of
storage based on data access requirements and then automatically and
nondisruptively moves data, at the subvolume or sub-LUN level, to the
appropriate tier on the DS8000.
Use Easy Tier to dynamically move your data to the appropriate drive tier in your
system with its automatic performance monitoring algorithms. You can use this
feature to increase the efficiency of your SSDs and the efficiency of all the tiers in
your DS8000 system.
You can use the features of Easy Tier between three tiers of storage within your
system on the DS8700 and DS8800 storage units.
With the latest Easy Tier you can distribute your entire workload among the ranks
in your storage pool using three tiers, more efficiently distributing bandwidth
across tiers in addition to IOPS.
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Introduction and Planning Guide