Optimized for virtualization and database applications with maximum
memory and compute capacity in a blade
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Reliability guidelines:
• Using fewer, larger DIMMs (for example 8 x 4 GB DIMMs vs. 16 x 2GB DIMMs is generally more
reliable
• Xeon 7500 Series memory controllers support IBM Chipkill memory protection technology with x4
DIMMs (x4 data width of rank) and x8 DIMMs
For increased availability beyond Chipkill error correction, t he eX5 servers offer additional levels
of IBM Active Memory protection:
Memory ProteXion technology provides multichip error prot ection and works in conjunction with
Chipkill technology—which provides multibit protection p er chip—and standard ECC protection,
to provide multi-level memory correction.
With memory rank sparing, two unused ranks per memor y card are configured as spares.
These spare ranks are used in the event of a memory f ailure on the same memory card.
Memory mirroring works much like disk mirroring. The tot al memory is divided into two
channels. Data is written concurrently to both channels. If a DIMM fails in one of the DIMMs in
the primary channel, it is instantly disabled and the mirror ed (backup) memory in the other
channel becomes active (primary) until the failing DIMM is r eplaced. With mirroring enabled,
one-half of total memory is available for use. (Note: Due to t he double writes to memory,
performance is affected.) Mirroring is handled at the hardwar e level; no operating system
support is required.
Memory scrubbing is an automatic daily test of all system mem ory. It detects and reports
memory errors that might be developing before they caus e a server outage. Memory scrubbing
and Memory ProteXion work together. When a bit error is detected, memory scrubbing
determines whether the error is recoverable. If the error is r ecoverable Memory ProteXion
technology will write the data to new location; if it is not recov erable, scrubbing sends an alert to
light path diagnostics, which then notifies IBM Systems Direct or.
Memory is available in 2GB, 4GB, 8GB, or 16GB DIMMs.
High-Performance Scalability Because of eX5 design, an HX5 server has the incredible fl exibility of scaling from 2 sockets to 4
sockets with ease, doubling the memory and storage capac ity and I/O slots in the process. A 2-
node configuration is achieved simply by connecting 2 30 mm blades together via the Quick Path
Interconnect (QPI) ports, for 4 sockets and 32 DIMMs (256G B).
Alternatively, you can scale via MAX5, adding memory c apacity to increase performance in an
I/O-intensive enironment. This configuration connects 1 HX5 blade to 1 MAX5 blade, for a total
of up to 40 DIMMs (320GB), If even that’s not enough, you c an connect 2 HX5 blades to 2
MAX5 blades, and the two MAX5 units are cabled togeth er using our exclusive EXA scalability
kit. The result is a powerhouse 4-socket, 80 DIMM (640G B) blade server in only 120mm.
Note: Selected models of HX5 come standard with a MAX5 blade.
This scalability and memory expansion feature is a unique IBM enhancement, not offered by
other x86 server architectures.
XceL4v Dynamic Server Cache A key performance feature of MAX5 expansion is the XceL4v L4 cache. When using a single
HX5 blade with a MAX5 expansion unit, no virtual cach e needs to be taken from main memory.
However, when multiple MAX5 nodes are connected, 256M B of L4 cache is allocated from main
memory used for interprocessor communications between ch assis, to keep data in synch. In a 2-
chassis configuration, this amounts to 512MB of L4 cache. T his not only compensates for any
performance hit that might otherwise result from sending data across the distances between
processors in multiple chassis, it actually results in a perf ormance improvement versus a single
chassis. (IBM X3, eX4 and eX5 servers have achieved well over 100 #1 results on industry-
standard benchmarks, such as TPC-C, TPC-E, TPC-H, SAP S D, vConsolidate, Vmark, and
more.)
This feature is another IBM-unique enhancement.
Integrated Virtualization
HX5 offers a separately orderable IBM 2GB USB Flash Drive option preloaded with VMware
ESXi 4.0 (an embedded version of VMware ESX Server). Micr osoft Hyper-V and Xen are also
supported, installed by the user on an SSD.
ESXi is fully contained on the flash drive, without requiring any disk space. Because it runs from
flash memory, it’s extremely fast and ideal for diskless c onfigurations. It also offers enhanced
security, because it runs without an operating system-based c onsole and is updated/patched
much like firmware. ESXi includes all the performance, sc alability and compatibility features of