Server Snapshots: IBM BladeCenter LS21 and LS41

By Drew Robb (Send Email)
Posted Nov 30, 2007


It's been more than a year since IBM (Armonk, N.Y.) unveiled an extensive line of AMD-Opteron-based products for its System x and BladeCenter lines. Several months ago, it added the three newest members of the BladeCenter family, including two blades, the LS21 and LS41. Both deliver high throughput and are scalable.

With the dual-core LS21 and LS41, IBM made BladeCenter an option for high-performance computing as well as consolidation. Now, it's looking ahead to quad core.

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The LS21 uses up to two AMD dual-core Opteron 2000 series processors, while the LS41 uses up to four Opteron 8000 series chips. They run at speeds of up to 3.0 GHz with 1 MB L2 cache per core and are available in 95 W and 68 W versions.

"With the unveiling of a broad and deep AMD-Opteron-based lineup last summer, IBM has left little doubt that — even if they also remain important Intel partners — they'll ride the AMD horse equally hard," said Gordon Haff, an analyst at Illuminata (Nashua, N.H.). "Its latest LS21 and LS41 Opteron-based blades leverage other BladeCenter ecosystem capabilities. They're about far more than high-performance computing. They explicitly target enterprise apps; they're also all over the rapidly-growing virtualization use case."

Little and Large

Footprint-wise, the LS21 is the smaller of the two — it is half the width of the LS41. It comes with one Opteron dual-core chip standard and can hold a maximum of two. Being the smaller of the two servers, the LS21 has room for only one Serial Attached SCSI (SAS) hard drive (36.4 GB or 73.4 GB). It can run a wide range of operating systems — Red Hat and SUSE Linux, Windows Server 2003 and Solaris 10. Up to 32 GB of RAM is available. On the networking side, it comes with two integrated Gigabit Ethernet controllers. It also has one PCI-X expansion connector and another PCI-Express connector.

"The LS21 supports a healthy complement of memory and integrated networking," said Haff. "It also comes with a single SAS drive; in addition to standard NAS or SAN shared storage, additional disks can be configured using the BladeCenter Storage and I/O Expansion blade."

Pricing officially begins at $2,299, although a sale price as low as $1,839 has recently been on offer. Bear in mind that should you customize the server by adding a more powerful processor, an extra processor and more memory, the price can rise significantly.

The LS41, on the other hand, has one or four Opteron dual-core 8000 processors, RAM in the 2 GB to 64 GB range, room for two SAS drives, and a total of four PCI-X and PCI-Express connectors. Pricing starts at $8,199 (sale prices of $6,149 may still be available as of press time) and buys you two x 2 GHz dual-core Opteron processors, 2 GB RAM and no hard drives. A model with two x 2.6 GHz dual-core Opteron processors with 4 GB RAM and no hard drives, on the other hand, is priced at $7,349 (sale price).

"Both the LS21 and LS41 are ideal for high-performance computing," said Botond Kiss of IBM BladeCenter product marketing. "The main distinction between the two is that the LS41 supports up to four multicore processors vs. the LS21's two, making the LS41 ideal for the most compute-intensive jobs."

The LS41 consists of two dual-socket blades glued together with additional HyperTransport connectors. This is the same interconnect Opteron processors use to communicate with each other and with I/O devices. The design enables two dual-socket blades to be combined into a single, double-width blade with four sockets.

Kiss said both the LS21 and LS41 are commonly used as a platform for consolidation. He said a bank in Michigan, for example, in an effort to lower power consumption and improve operational efficiency, recently consolidated its older servers on to IBM BladeCenter LS21 and LS41 servers running VMware software.

These IBM blades, said Kiss, typically go up against 2- and 4-processor AMD c-class blades from HP (Palo Alto, Calif.), and, more recently, HP's 4-processor c-class Intel blade. In his mind, the LS blades are more scalable and more power- and space-efficient.

"They can scale from a 2-socket server to a 4-socket server by simply snapping on an expansion unit," said Kiss. "In terms of power, cooling and density, they support high-efficiency processors along with the industry-leading density and power efficiency via the BladeCenter E and BladeCenter H chassis."

These IBM Opteron blades can either have local disk capacity or adopt a 'diskless blade' strategy and consolidate all storage externally. This increases the reliability of blades by removing their only moving part. It also reduces power consumption further, according to IBM, and subsequently reduces heat by up to 50 percent.

Quad Core Coming

It will not be long, of course, before IBM further upgrades the LS21 and LS41 with quad-core Opteron processors.

"We plan on supporting AMD's quad-core processor in the near future and will continue our strong collaboration with AMD on future products," said Kiss.

Meanwhile, the current dual-core processors are socket-compatible with upcoming quad-core Opterons. As soon as the chips become available, look for the LS41, in particular, to be used for even heavier duty purposes. In fact, Haff said he believes this blade will be more potent than midrange systems of not so long ago.

"From SAP applications to Microsoft SQL Server to IBM's DB2 to Oracle's database and applications, the eight cores (soon to be 16) in a server like the LS41 have more performance than a large RISC server of just a few years back," said Haff.

The LS21 and LS41 Close Up

Name LS21 LS41 The LS21
Source: IBM

The LS41
Source: IBM
Vendor IBM IBM
Platform x86 x86
Dimensions 29mm x 245mm x 446mm 58mm x 245mm x 446mm
Processor Details Up to two AMD dual-core Opteron processors (2000 series) running at speeds of up to 3.0 GHz Up to four dual-core Opteron 8000 series processors running at speeds of 2.0 GHz, 2.4 GHz and 2.6 GHz with 1 MB L2 cache per core
Hard Drives Room for one 36.4 GB or 73.4 GB SAS drive internally Up to two SAS drives (maximum internal storage, 146 GB)
Operating Systems Red Hat Linux, SUSE Linux, Windows 200x, Solaris Red Hat Linux, SUSE Linux, Windows 200x, Solaris
Configuration Options $1,839 for one dual-core 2 GHz Opteron processor, 1 GB RAM and no hard drive
$2415 for one dual-core 2.6 GHz processor, 2 GB RAM and no hard drive
$6,149 for two x 2 GHz dual-core Opteron processors, 2 GB RAM and no hard drives
$7,349 for 2 X 2.6 GHz dual-core Opteron processors with 4 GB RAM and no hard drives
Availability Now available Now available
Warranty Three years Three years

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