HP SmartCache technology

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The Smart Array P421 controller disk configuration included the following:

• Boot Volume: 2 - 72GB 10K 6G SAS drives configured in RAID 1

• Database Logs: 4 - 300GB 10K 6G SAS drives configured in RAID 5

• Database: 12 - 300GB (10K 6G SAS drives configured in RAID 1+0

• HP SmartCache: 1 – 100GB SSD MLC 6G SSD drive configured in RAID 0. The HP SmartCache was configured in write-

through mode and assigned to cache the database volume

The database size was roughly 1.6TB during the two-hour run. Figure 5 shows the performance of the TPCe-like workload

both with HP SmartCache (red) and without HP SmartCache (blue). TPeS performance of the TPCe-like workload was

significantly better when using HP SmartCache. The SSD used as a cache was less than 7% the capacity of the database. The

cache-hit ratio of HP SmartCache was 84%, meaning that roughly five out of every six disk reads to the database volume

were serviced by the SSD versus the HDDs. A smaller amount of HP SmartCache would have yielded a smaller cache hit

percentage and lower performance gains.

Figure 5. TPCe-like workload performance with and without HP SmartCache.

Table 1 compares the database logical volume IO statistics without and with HP SmartCache. With the addition of the HP

SmartCache, performance results change dramatically simply by adding a 100-GB SSD.

Table 1. TPCe-like workload statistics

I/O Analysis

Without HP SmartCache

With HP SmartCache

Accesses 32,767,015 159,239,037 (almost 5x more)

Reads 29,114,040 140,159,417 (almost 5x more)

Writes 3,652,975 19,079,620 (5x more)

% reads 89 88

TPeS

Time in seconds