RAS Features of the Intel Xeon Scalable Processors on Lenovo ThinkSystem ServersArticle

Updated
31 Mar 2022
Form Number
LP1571
PDF size
9 pages, 108 KB

Abstract

Server reliability, availability, and serviceability (RAS) are crucial issues for modern enterprise IT shops that deliver mission-critical applications and services, and application delivery failures can be extremely costly per hour of system downtime. Intel Xeon Scalable Processors running on ThinkSystem servers continue to be at the top of the industry in regards to RAS features. This article explains the importance of RAS features on a server and a list of Key RAS features on the latest ThinkSystem servers Lenovo offers to customers looking to minimize downtime in their data center.

Introduction

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.

Always On

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

The Cost of Downtime

The ITIC 2021 survey found that 99% of organizations say that a single hour of downtime costs over $100,000; 91% of respondents indicated that 60 minutes of downtime costs their business over $300,000 and a record one-third or 44% of enterprises report that one hour of downtime costs their firms $1 million to over $5 million.

Cost of hourly downtime in enterprises, 2016-2017
Figure 1. Cost of hourly downtime in enterprises, 2020-2021

Server RAS Defined

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

RAS Features of Lenovo ThinkSystem Servers with Intel Xeon Scalable Processors

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

Platinum and Gold level processors support both Advanced and Standard RAS features. Silver processors only support Standard RAS features.

Table 1. Key RAS Features of the Intel Xeon Scalable Processors on the Lenovo ThinkSystem servers
Advanced RAS features Category 2nd Gen Intel Xeon Scalable Processors ("Purley") 4-Socket 3rd Gen Intel Xeon Scalable Processors ("Cedar Island") 2-Socket 3rd Gen Intel Xeon Scalable Processors ("Whitley") Benefit
Viral Mode of error containment Reliability Yes Yes Yes Enhanced error containment to improve data integrity, complimentary to corrupt data containment mode
Local Machine Check (LMCE) based Recovery Reliability Yes Yes Yes Enhances MCA recovery-Execution path event, and increases the possibility of recovery
SDDC +1, Adaptive DDDC (MR) +1 Reliability Yes Yes Yes Adaptive virtual lockstep delivers up to two DRAM Device corrections. Also supports Single DRAM correction, as well as single bit correction post final DRAM device map out.
PCI Express Live Error Recovery Reliability Yes Yes Yes PCI-e root port error containment, and the opportunity to dynamically recover from the error
Intel® UPI Dynamic Link width reduction Availability Yes Yes Yes Enables interconnect to continue operation in presence of Interconnect link persistent failure
Address range/Partial Memory Mirroring Reliability Yes Yes Yes OS managed memory mirroring of selective ranges, increases data integrity at efficient cost
MCA 2.0 Recovery (as per eMCA gen2 architecture) Reliability Yes Yes Yes Firmware first model enables a reliable error sourcing capability with the ability to write to the MSR
Standard RAS features Category 2nd Gen Intel Xeon Scalable Processors ("Purley") 4-Socket 3rd Gen Intel Xeon Scalable Processors ("Cedar Island") 2-Socket 3rd Gen Intel Xeon Scalable Processors ("Whitley") Benefit
Advanced Error Detection and Correction (AEDC) Reliability Yes Yes Yes Enhanced fault coverage within processor cores, and attempt to recover via instruction retry
Error Detection and Correction Reliability Yes Yes Yes Extensive Error detection and correction capability across the silicon, and the interconnects.
Corrupt Data containment-Core Reliability Yes Yes Yes Uncorrectable data explicitly marked and delivered synchronously to the consuming core to assist error containment and increase system reliability
Corrupt Data containment-UnCore Reliability Yes Yes Yes Uncorrectable data explicitly marked and delivered synchronously to the requestor, to assist error containment and increase system reliability
SDDC, Adaptive Data Correction (SR) Reliability Yes Yes Yes Adaptive virtual lockstep delivers single DRAM Device corrections, at bank granularity. Also supports Single DRAM correction.
PCIe “Stop and Scream” Reliability Yes Yes Yes PCI-e root port corrupt data containment feature, increases data integrity
Memory Mirroring- Intra iMC Reliability Yes Yes Yes Increase data integrity by creating a redundant/mirrored copy of data in system DRAM
DDR4 memory RANK Sparing Reliability Yes Yes No Reserved/spare DRAM RANKs are utilized to dynamically map out the failing DRAM RANK into the spare Ranks.
Predictive Failure Analysis Serviceability Yes Yes Yes Extensive error logs to assist software in predicting failures
Failed DIMM Isolation Serviceability Yes Yes Yes Extensive error logs to help software identify the failing DIMM
Virtual (soft) Partitioning Reliability Yes Yes Yes Virtual Machine Monitor ability to make use of hardware recovery , signaling and error logs
Error reporting via IOMCA Serviceability Yes Yes Yes Unified error reporting of the IIO logic to the OS
Error reporting through MCA 2.0 (eMCA gen2) Serviceability Yes Yes Yes Firmware first model enables a reliable error sourcing capability
Error reporting through eMCA gen1 Serviceability Yes Yes Yes Firmware first model enables reliable error sourcing capability
PCIe Card Hot Plug NVMe (Add, Remove, Swap) Serviceability Yes Yes Yes Hot add and repalce of NVMe drives
PCI Express ECRC Reliability Yes Yes Yes PCI Express End to end CRC checking, increasing system reliability
PCIe Corrupt Data Containment (Data Poisoning) Reliability Yes Yes Yes PCIe corrupt data mode of operation, synchronous signaling of the corrupted data along with data, increases system reliability
PCIe Link CRC Error Check and Retry Reliability Yes Yes Yes PCIe link CRC error check and retry, system reliability and recovery from transient errors
PCIe Link Retraining and Recovery Reliability Yes Yes Yes PCIe link retraining and attempted recovery from persistent link transient errors
Mem SMBus hang recovery Reliability Yes Yes Yes Software ability to reset memory SMBus interface to recover from hang condition
DDR4 Command/ Address Parity Check and Retry Reliability Yes Yes Yes DDR4 Address and command parity check and retry in the event of errors
Time-out timer Schemes Serviceability Yes Yes Yes Hierarchy of transaction time outs to assist system debug and reliable error sourcing.
Intel® UPI Link Level Retry Reliability Yes Yes Yes Intel UPI link’s ability to perform CRC check and retry on errors for higher degree of system reliability
Intel® UPI Protocol Protection via 16 bit Rolling CRC Reliability Yes Yes Yes Detection of transient data errors over Intel UPI interconnects, via 16bit CRC error checking
Processor BIST Serviceability Yes Yes Yes At power up, Processor’s built in self test engine performs test on the internal cache structure for and provides the results to the system BIOS
Socket disable for FRB Availability Yes Yes Yes The capability to selectively disable socket at the boot time, and therefore allowing system to power-on in a failover configuration
Core disable for FRB Availability Yes Yes Yes The capability to disable failing cores at boot time, map out the failing core
PIROM for System Information Storage Serviceability Yes Yes Yes On package Processor Information ROM
MCA Recovery-Execution path Reliability Yes Yes Yes OS layer assisted recovery from uncorrectable data errors to prevent system reset
MCA Recovery-Non execution path Reliability Yes Yes Yes OS layer assisted recovery from uncorrectable data errors detected by Patrol scrubber or LLC Explicit Write Back
DCU Scrubbing Reliability No No Yes Improves system uptime by minimizing the impact due to high energy particle strike (Soft Errors) within core DCU (aka L1D cache)
Partial Cache Line Sparing (PCLS) Reliability No No Yes Extend system uptime in case a single bit memory persistent error is detected. It allows mapping out the cache line with failed single bit by using spare capacity available within the IMC
PCIe Enhanced Downstream Port Containment (EDPC) Reliability No No Yes EDPC is an enhancement to the Downstream Port Containment (DPC) thereby adding Root Port Programmable IO (RPPIO) errors.
DCU/IFU Error Handling Enhancement Reliability No No Yes Improving MCA Recovery (Execution path) coverage in case CPU core (DCU/IFU) receives multiple back-to-back read data with ‘Poison Error’ (aka Poison Storm).

Conclusion

Lenovo ThinkSystem servers equipped with the newest generations of Intel Xeon Scalable Processors have maintained RAS features leadership. This translates into Reliability, Serviceability and Availability for all types of workloads required by enterprises, saving thousands of dollars by avoiding downtime of service.

About the author

Randall Lundin is the Mission Critical Product Manager in the Lenovo Infrastructure Solutions Group. He is responsible for managing and planning Lenovo’s 4-socket and 8-socket servers. Randall has also authored and contributed to numerous Lenovo Press publications in the Mission Critical space.

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