How we added RAM to HPE servers

The quality and reliability of DRAM is now more important than ever, mainly due to the increasing use of server virtualization. Of course, it is worth noting that RAM modules, according to many IT specialists, are among the most reliable server elements and fail the latter. Virtualization has many advantages, but it significantly increases the amount of memory needed in the server for optimal performance of the maximum number of virtual machines. According to HP, for 5 years from 2007 to 2011, the average memory installed on all HP ProLiant servers has grown by more than 500% - from 4 GB to more than 30 GB per server.

Currently, as a cloud provider, we are using HP ProLiant BL460c Gen8 blades on the HPE BLADESYSTEM C7000 ENCLOSURE chassis. Fully QuickSpecs here , we denote only the RAM specification.

Standard (Preconfigured Models)
64GB (8 x 8GB) DDR3 1600MHz RDIMMs at 1.5V
64GB (4 x 16GB) DDR3 1866MHz RDIMMs at 1.5V
32GB (4 x 8GB) DDR3 1600MHz RDIMMs at 1.5V
32GB (2 x 16GB) DDR3 1866MHz RDIMMs at 1.5V
32GB (4 x 8GB) DDR3 1333MHz RDIMMs at 1.35V
32GB (2 x 16GB) DDR3 1600MHz RDIMMs at 1.35V
16GB (2 x 8GB) DDR3 1866MHz RDIMMs at 1.5V
16GB (4 x 4GB) DDR3 1333MHz RDIMMs at 1.35V
16GB (2 x 8GB) DDR3 1600MHz RDIMMs at 1.35V
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Maximum
(LRDIMM) 512GB (16 x 32GB) up to 1333MHz at 1.35V
(RDIMM) 256GB (16 x 16GB) up to 1866MHz at 1.5V
(RDIMM) 384GB (16 x 24GB) up to 1333MHz at 1.35V
(UDIMM) 128GB (16 x 8GB) up to 1600MHz at 1.5v

If you need help to understand the notation of memory types and their differences, we recommend a useful article on Habré .

Note that in the case of using the equipment for the cloud, that is, in systems requiring scalability and fault tolerance at the expense of low cost, the register memory with the error correction function (ECC RDIMM) is used.

To improve the performance of our cloud environment in accordance with the growing needs of customers, we decided to increase the amount of RAM in the servers to the maximum possible values. There was a logical question what kind of memory to buy? It was logical to start the selection from the acquaintance with the proposal of the server manufacturer, which was done.

In search of a concise answer, White paper from HP was found, more precisely, even two, one in 2011 , and the second in 2017 . What we have identified for ourselves :

• HP is not a manufacturer of RAM modules.
• When you see the HP Qualified Memory brand, it means that DRAM has undergone a serious quality check and testing with proprietary diagnostic tools and specialized diagnostic tests to ensure a high level of performance and availability of HP ProLiant servers.
  
  
  
  
• Before the DRAM module receives the HP Qualified Memory brand (sticker), it undergoes an intensive four-phase quality assurance process. HP long before product development informs memory module manufacturers (Tier 1 memory suppliers) DRAM requirements. The HP Memory Core team receives DIMMs directly from the manufacturer. The HPMQ process diagram (HP Memory Qualification) provides brief descriptions of the four phases of the quality assurance process. In our opinion, it is important to pay attention to the fact that it is not described what proportion of the modules received for testing is eliminated.
  
  
  As a result, HPMQ does not change the location of the chips, it seems the designer made a mistake
  
  
• The memory is checked so that it does not become too hot and for this reason has not forgotten your data.
  

  It doesn’t get too hot. It doesn’t cause the system to shut down due to power overload.

• HP Qualified Memory has the same full warranty as the ProLiant servers.
• If it is determined that a server failure is caused by RAM under a different brand (non-hp), or at any time it is discovered that a third-party part is detrimental to HP components or systems, the cost of repairs, including damaged HP parts, labor and travel, will not be covered under standard HP warranty. But installing third-party memory does not remove the ProLiant server from the HP warranty. This misconception is often cited by users of IT forums as an “over OEM” argument during the discussion of server memory selection.
  

How much does HPMQ and HP service cost for the customer? For clarity and understanding of the price level, screenshots from Yandex.Market are attached. We do not propose to regard this as a full-fledged market research, especially due to the low prices for HP RAM from unknown vendors, which are 60% lower than the average market.





Why did we choose Kingston for comparison?

• Each Kingston server module for a particular system must pass a forced failure test. This unique procedure allows you to reject potentially defective modules, preventing them from falling into the shipped production batches. Including, there is a test of reliability during heating. Full list of quality checks here .
• As a long-term member of the JEDEC Board of Directors, Kingston Technology contributes to the creation of industry standards for memory technology. All memory modules manufactured by Kingston meet the requirements of JEDEC and the basic specifications used by leading manufacturers of semiconductor devices.
• Technical support and test drive. There is an official representation in the Russian Federation (unlike Crucial, for example), upon request there is always the required number of dies for shipment. Server memory can be taken for a test drive and see how it will work in real conditions on a specific server.
• "Lifetime" warranty. If the memory module fails, it will be replaced under warranty.

Kingston has a large number of different RAM module options. You can find a suitable one on their website. Potential incompatibility problems should be absent, since according to the statements of Kingston, the modules were tested on all relevant server variants. In our case, we chose for the HP BL460C G8, there were no problems in the work.

What did the purchase of Kingston memory modules give us? With a significant amount of purchases, it was possible to seriously reduce the budget for modernization. We were unable to identify significant differences in the quality control of RAM from Kingston and HP. Finding no reason to pay almost twice the bill, we chose Kingston modules. It also made it possible not to transfer additional costs to consumers of our services.

In this article we are not trying to draw attention to the high cost of components from HP. Moreover, we are pleased with the use of HP ProLiant servers and HP BladeSystem. To support a large number of virtual machines on a single physical server, more memory, more connections for data storage and more network connections are required, therefore, in our opinion, HP servers certified for VMware are among the best virtualization platforms since they were built "With virtualization in mind".

VMware certification gives us the ability to consistently use all VMware virtualization platform options, which significantly increase the efficiency and reliability of the entire cloud:

• VMware VMotion;
• VMware DRS;
• VMware HA;
• and others.

The selected equipment for the cloud provider is the basis for building the entire business system, which ultimately must provide customers with services with a high level of availability and quality (SLA from 99.95%) at a competitive price. This is the reason for finding the best solutions.