Chapter 5. IBM BladeCenter HX5 207
5.11.3 Determining which SSD RAID configuration to choose
Using an industry standard IO tool that measures hard drive performance, we tested each
available configuration type. We used two separate tests: one test using 50% sequential
reads and 50% random writes (Figure 5-22) and the other test using 90% sequential reads
and 10% random writes (Figure 5-23). We tested each group using 16 KB, 512 KB, and 1 MB
transfer request sizes, which are the most common transfer request sizes that are used in
server environments today.
Figure 5-22 Showing 50% Sequential/50% Random test results
Figure 5-23 Showing 90% Sequential/10% Random test results
We ran these tests on an HX5 2-node system running four 2 GHz Intel Xeon 7500 series
6-core processors and 16 GB of memory. The SSDs were IBM 50 GB SATA 1.8-inch NHS
SSDs. Results might vary depending on the size and type of installed drives.
The results show that when choosing a configuration for setting up hard drives, the
performance difference between a RAID-1, RAID-0, and JBOD configuration is minimal.
JBOD was always the fastest performer, followed by RAID-1, and then RAID-0.
5.11.4 Connecting to external SAS storage devices
The SAS Connectivity Card (CIOv) for IBM BladeCenter is an expansion card that offers the
ideal way to connect the supported BladeCenter servers to a wide variety of SAS storage
devices. The SAS Connectivity Card connects to two SAS Controller Modules in the
BladeCenter chassis. You can then attach these modules to the IBM System Storage DS3200
from the BladeCenter H or HT chassis, or Disk Storage Modules in the BladeCenter S.
SAS signals are routed from the LSI 1064E controller on the SSD Expansion Card to the SAS
Connectivity Card, as shown in Figure 5-24 on page 208.
Two of the SAS ports (SAS 0 and SAS 1) from the LSI 1064E on the SSD Expansion Card
are routed to the 1.8-inch SSD connectors. The other SAS ports (SAS 2 and SAS 3) are
routed from the LSI 1064E controller through the server planar to CIOv connector, where the
SAS Connectivity Card (CIOv) is installed.
Tests: These tests are not certified tests. We performed these tests to illustrate the
performance differences among the three configuration options.
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