Memory Operation; Data Protection - HP XP P9500 Owner's Manual

Figure 16 Cache memory
Table 15 Cache memory
Item Description
1 Micro Processor Blade
Includes 4 GB cache
3 Micro Processor Blade cluster 0
5 Cache cluster 0
7 Cache cluster 2

Memory operation

The P9500 places all read and write data in the cache. The amount of fast-write data in cache is
dynamically managed by the cache control algorithms to provide the optimum amount of read
and write cache, depending on the workload read and write I/O characteristics.
Mainframe hosts can specify special attributes (for example, cache fast write command) to write
data (typically sort work data) without write duplexing. This data is not duplexed and is usually
given a discard command at the end of the sort, so that the data will not be destaged to the drives.

Data protection

The P9500 is designed so that it cannot lose data or configuration information from the cache if
the power fails. The cache is protected from data loss up for up to ten minutes by the cache destage
batteries while the data is copied to the cache SSD (flash memory) on the cache boards (see
"Battery backup operations" (page
60 System components
Item Description
2 Cache Memory Adapter:
8, 16, or 24 GB standard
32 GB SSD drives optional
1 or 2 16 GB SSD drives
4 Micro Processor Blade cluster 1
6 Cache cluster 1
8 Cache cluster 3
67)).