GLYPH<SM590000> Error Recovery 

GLYPH<SM590000> System Recovery Boost 

With a properly configured z15 server, further reduction of outages can be attained through First Failure Data Capture (FFDC), which is designed to reduce service times and avoid subsequent errors. It also improves nondisruptive replace, repair, and upgrade functions for memory, drawers, and I/O adapters. z15 servers support the nondisruptive download and installation of LIC updates. 

IBM z15™ RAS features provide unique high-availability and nondisruptive operational capabilities that differentiate the Z servers in the marketplace. z15 RAS enhancements are made on many components of the CPC (processor chip, memory subsystem, I/O, and service) in areas, such as error checking, error protection, failure handling, error checking, faster repair capabilities, sparing, and cooling. 

The ability to cluster multiple systems in a Parallel Sysplex takes the commercial strengths of the z/OS platform to higher levels of system management, scalable growth, and continuous availability. 

The z15 processor builds upon the RAS of the z14 family with the following RAS improvements: 

GLYPH<SM590000> System Recovery Boost 

System Recovery Boost was introduced with IBM z15. It offers customers more Central Processor (CP) capacity during system recovery operations to accelerate the system startup (IPL), shutdown or stand-alone dump operations. System Recovery Boost requires operating system support. No other IBM software charges are made during the boost period. 

System Recovery Boost might be used during LPAR IPL or LPAR shutdown to make the running operating system and services available in a shorter period. 

The System Recovery Boost provides the following options for the capacity increase: 

– Subcapacity CP speed boost: During th e boost period, subcapacity engines are transparently activated at their full capacity (CP engines). 

– zIIP Capacity Boost: During the boost period, all active zIIPs that are assigned to an LPAR are used to extend the CP capacity (CP workload is dispatched to zIIP processors during the boost period). 

At the time of this writing, the main System Recovery Boost users are z/OS (running in an LPAR), z/VM, and z/TPF. 

z/VM uses the System Recovery Boost if it runs on subcapacity CP processors only (IFLs are always at their full clock speed). Second-level z/VM guest operating systems$^{10}$ can inherit the boost if they are running on CPs. 

GLYPH<SM590000> Level 3 and Level 4 cache enhancements use symbol ECC to extend the reach of prior z14 cache and memory improvements for improved availability. The level 3 and level 4 cache powerful symbol ECC is designed to make it resistant to more failure mechanisms. Preemptive DRAM marking is added to the main memory to isolate and recover failures more quickly. 

GLYPH<SM590000> On-chip compression accelerating compression operations on core level, for all LPARs, which eliminates the virtualization layer that was needed for zEDC Express. The technology replaces zEDC Express PCIe cards, which improves reliability and availability. 

