A new high density cache memory feature from Sun allows upgrades to 128
GB of cache memory on the Sun StorEdgeTM 9980 storage system and up
to 64 GB on the Sun StorEdgeTM 9970 system. There is also a new
shared memory module that can extend capacity to 4 GB on the above
mentioned storage systems when total cache memory capacity is 64 GB or
The nonvolatile cache memory has 48-hour battery backup and duplicates
write data to prevent data loss even when a failure of one component
occurs in the power supply or a PCB. This new high density Cache Memory
module requires the installation of the new Shared Memory module also
being made available as part of this announcement.
The larger cache will improve performance of write-intensive
applications and random I/O applications. To assist the performance of
these applications, now even more data can be "locked" into cache in
real time with Sun StorEdgeTM 9900 FlashAccess cache residency manager
software, allowing read and write functions to be performed at cache
speeds, with no disk latency delay.
In addition, those users deploying disaster recovery solutions based on
the Sun StorEdgeTM 9900 TrueCopy asynchronous technology will also
experience a major benefit since the extra cache space will enhance the
ability of the 9980 and 9970 systems to handle the pending transfer
The nonvolatile shared memory has seven-day battery backup and can be
used to store cache directories and disk control information. The
capacity of shared memory varies with the capacity of cache memory
mounted and the storage capacity (number of LDEVs).
The value for users is better response time. For example, in a
read-only situation, more data can be brought into cache so that
searches can be conducted at electronic rather than electro-mechanical
speeds. In a write situation, writes can be batched and written in a
sequential/efficient manner. In both cases, response times are
Both the high density cache memory and the shared memory module are
built with 512 MB DRAM versus the current 256 MB DRAM. Users should
note that, while these DRAMs can be run in high performance mode, they
must be done so separately and cannot be mixed if that is the user's
intention. Furthermore, the installation of these memory modules must
be considered semi-disruptive because half of the cache memory will be
taken off line and not available to the host during the installation of
each cluster of the control unit.
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