13.1 Reliability, availability, and serviceability Reliability, availability, and serviceability (RAS) are important concepts in the design of the  IBM Spectrum Virtualize system. Hardware features, software features, design  considerations, and operational guidelines all contribute to make the IBM Storwize V7000  system reliable.  Fault tolerance and high levels of availability are achieved by using the following methods: High levels of serviceability are available through the following methods: GLYPH<SM590000> The Redundant Array of Independent Disks (RAID) capabilities of the underlying disks GLYPH<SM590000> IBM Storwize V7000 nodes clustering using a  Compass  architecture GLYPH<SM590000> Auto-restart of hung nodes GLYPH<SM590000> Integrated Battery Backup Units (BBU) to provide memory protection if a site power failure  occurs GLYPH<SM590000> Host system failover capabilities using N-Port ID Virtualization (NPIV) GLYPH<SM590000> Cluster error logging GLYPH<SM590000> Asynchronous error notification GLYPH<SM590000> Automatic Dump capabilities to capture software detected issues GLYPH<SM590000> Concurrent diagnostic procedures GLYPH<SM590000> Directed Maintenance Procedures (DMP) with guided online replacement process GLYPH<SM590000> Concurrent log analysis and memory dump data recovery tools GLYPH<SM590000> Concurrent maintenance of IBM Storwize V7000 components GLYPH<SM590000> Concurrent upgrade of IBM Storwize V7000 Spectrum Virtualize Software and firmware GLYPH<SM590000> Concurrent addition or deletion of node canisters in the clustered system GLYPH<SM590000> Automatic software version leveling when replacing a node GLYPH<SM590000> Detailed status and error conditions that are displayed by LED indicators GLYPH<SM590000> Error and event notification through Simple Network Management Protocol (SNMP),  syslog, and email GLYPH<SM590000> Optional Remote Support Assistant The heart of IBM Storwize V7000 system is a pair of  node canisters . These two canisters  share the read and write data workload from the attached hosts and to the disk arrays. This  section examines the RAS features of IBM Storwize V7000 system, monitoring, and  troubleshooting. Throughout this chapter, the term  IBM Storwize V7000  refers to both models of the product:  IBM Storwize V7000 Gen2 and Gen2+. 674  Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1