Tiered Storage Optimization
137
Performance and Optimization
Dynamic Cache
Partitioning
This offering (a separate feature from Symmetrix Priority Controls)
allows modification of cache allocation for devices configured in the
Symmetrix in order to help organizations manage multiple
applications with tiered storage in the array. Cache partitioning is a
logical partitioning of cache. Using Tag-based Caching (TBC), cache
partitioning provides the ability to divide cache into eight cache
partition groups (CPGs). (Seven user defined groups in addition to
the default group.)
With Dynamic Cache Partitioning enabled, the cache subsystem is
aware of user defined allocations and ensures that CPGs do not
consume more cache than they are allotted. Each partition will have a
target cache percentage as well as high and low watermarks.
Partitions can be static or dynamic.
Dynamic Cache Partitioning is “dynamic” in that it will allow
donation of underutilized cache slots to other partitions after a user
specified donation time. The donation time equates to a measure of
cache use efficiency and inefficiently used cache resources can be
moved to other partitions. Partitions can also be static. Static
partitions remain fixed in size and the donation parameter is ignored.
Dynamic Cache Partitioning can be managed through the Solutions
Enabler (SE) command line interface or the intuitive graphical
Symmetrix Management Console interface. Both interfaces allow the
user to enable and disable cache partitioning, create, remove, and
modify cache partitions, add devices to and remove devices from
cache partitions, as well as view and list partitions and their related
statistics.
Power vault devices can’t be assigned to partitions. Special devices
(RDF, metadevices, striped CKD) have their own rules.
Also available to users is DCP “analysis mode,” which provides users
the ability to track a mix of device groups’ actual cache usage prior to
activating partitions. This helps users configure the appropriate
partition parameters.
To Next Page
Loading...
Need help?
General
