RAS Features of the Lenovo ThinkSystem Intel Servers

Applications such as database, enterprise resource planning (ERP), customer resource management (CRM), and business intelligence (BI) applications need to be available 24/7 on a wide area or global basis. In addition, the likelihood of such failures increases statistically with the size of the servers, data, and memory required for these deployments.

While clustering and virtualization can help meet availability requirements, they are not adequate solutions for very large databases, BI, and high-end transactional systems. A failure affecting a single core business application can easily cost hundreds of thousands or even millions of dollars per hour. All this leads to a need for scalable and highly resilient servers that are well suited for critical business applications and large-scale consolidation.

Time is money. Even a few minutes of downtime can result in significant costs and cause internal business operations to come to a standstill. Downtime can also adversely impact a company’s relationship with its customers, business suppliers and partners. Reliability or lack thereof can potentially damage a company’s reputation and result in lost business.

The growth of new applications has ratcheted database processing and business analytics to the top of the list for server workloads. These workloads demand continuous availability from the enterprise platforms on which they run.

"Always on" has become a global requirement and impacts many aspects of our lives:

• Maximize productivity - Manufacturers need to keep their production line up and running. System downtime should not interrupt it.
• Control access - Facility Security companies prevent external threats to organizations. Security application downtime shouldn't be an internal threat.
• Protect profit - Retailers have sales targets to meet day in, day out. Transaction system downtime shouldn’t get in the way.
• Protect lives - First Responders take care of emergencies 24 x 7 x 365. Application downtime shouldn’t be one of them.
• Ensure quality care and privacy - Healthcare Institutions need to access patient information and be HIPPA compliant all the time. System downtime shouldn’t compromise either one.
• Process transactions - Financial Services organizations manage thousands of transactions a second. Processing system downtime simply can’t happen

RAS in relation to servers is defined as follows:

Reliability – Reducing the mean time between hardware failures and ensuring data integrity. Data integrity is protected through error detection and correction — or, if not correctable, error containment

• Error Detection and Self-Healing
• Minimizes outage opportunities
• Correct results continuously

Availability – Refers to uninterrupted system and application operation even in the presence of uncorrectable errors

• Reduce frequency and duration of outages
• Self-diagnosing: work around faulty components or “self-heal”
• Never stops or slows down

Serviceability – Means a system can be maintained without disrupting operation. This capability requires both thoughtful platform design and innovative systems management.

• Avoid repeat failures with accurate diagnostics
• Concurrent repair on higher failure rate items
• Easy to repair and upgrade

90% of Companies survived say that 1 hour of downtime costs exceed $300K.

Figure 1. Hourly Cost of Downtime (from ITIC 2022-2023 Global Server Hardware reliability & Server Security Survey Results)

According to ITIC, Lenovo ThinkSystem and IBM lead the way for unplanned downtime

• Lenovo ThinkSystem: 1.1 minutes
• Cisco UCS: 2 minutes
• Dell PowerEdge: 26 minutes
• HPE ProLiant: 39 minutes

Figure 2. Unplanned Downtime by Server Hardware Platform in January 2023 (from ITIC 2022-2023 Global Server Hardware reliability & Server Security Survey Results)

The following table is a list of Key RAS Features of the Intel Xeon Scalable processors on the Lenovo ThinkSystem servers.

All ThinkSystem servers with Intel Xeon Scalable processors support the ADC (SR or Single Region) and ADDDC (MR or Multiple Region) feature which can support DRAM sub-region(s) sparing at Bank and/or full Rank granularity, compared to the memory rank sparing feature.

Details of Adaptive Double DRAM Device Correction (ADDDC) from the Intel article "New Reliability, Availability, and Serviceability (RAS) Features in the Intel® Xeon® Processor Family" https://www.intel.com/content/www/us/en/developer/articles/technical/new-reliability-availability-and-serviceability-ras-features-in-the-intel-xeon-processor.html

Intel Xeon introduces an innovative approach in managing errors that the DDR4 DRAM DIMM may induce through the life of the product. ADDDC is deployed at runtime to dynamically map out the failing DRAM device and continue to provide SDDC ECC coverage on the DIMM, translating to longer DIMM longevity. The operation occurs at the fine granularity of DRAM Bank and/or Rank to have minimal impact on the overall system performance.

With the advent of ADDDC, the memory subsystem is always configured to operate in performance mode. When the number of corrections on a DRAM device reaches the targeted threshold value, with help from the UEFI runtime code, the identified failing DRAM region is adaptively placed in lockstep mode where the identified failing region of the DRAM device is mapped out of ECC. Once in ADDDC, cache line ECC continues to cover single DRAM (x4) error detection and apply a correction algorithm to the nibble.

Dependent on the processor SKU, each DDR4 channel supports one to two regions that can manage one or two faulty DRAMs, at Bank and/or full Rank granularity. The dynamic nature of the operation makes the performance implications of the lockstep operation on the system to be material only after the DRAM device is detected to be failing. The overall lockstep impact on system performance is now a function of the number of bad DRAM devices on the channel, with the worst-case scenario of two bad Ranks on every DDR4 channel.

The Silver/Bronze SKUs offer Adaptive Data Correction (ADC [SR]), at Bank granularity, and the Platinum/Gold SKUs offer Adaptive Double DRAM Device Correction (ADDDC [MR]), at Bank and Rank granularity, with additional hardware facilities for device map-out.

For further analysis of the reliability of Lenovo servers, see the latest ITIC report, available from:

ITIC 2022-2023 Global Server Hardware Reliability & Server Security Survey Results:
https://lenovopress.lenovo.com/lp1117-itic-reliability-study

This article is one in a series on the ThinkSystem V3 servers:

• Five Highlights of the Lenovo ThinkSystem SR630 V3 Server
• Five Highlights of the Lenovo ThinkSystem SR650 V3 Server
• Five Highlights of the Lenovo ThinkSystem SR850 V3 Server
• Five Highlights of the Lenovo ThinkSystem SR860 V3 Server
• RAS Features of the Lenovo ThinkSystem Intel Servers

Randall Lundin is a Senior Product Manager in the Lenovo Infrastructure Solution Group. He is responsible for planning and managing ThinkSystem servers. Randall has also authored and contributed to numerous Lenovo Press publications on ThinkSystem products.