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Uma visão teórica e prática da operação de I/O no z13 e no DS888X (ou equivalente)
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Durante a aula discutiremos um conjunto de relatórios de desempenho.
Os principais tópicos principais são:
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Métricas de desempenho
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Tem o objetivo de manter o aluno atualizado . Cada nova função em hardware (como DS888X, por exemplo) ou em software (em z/OS V2R3, por exemplo) afetando I/O Storage estão incluidas, com exemplos de vida real.
A lista completa dos assuntos são:
· What a hell is an I/O operation
· Storage Pyramid
· Laws and Graphics
· 3390 geometry, CKD track format
· VTOC e Index VTOC
· A few ISPF screens
· PDS/PDSE organizations
· Tipos de acesso: Seqüencial, Randômico e Skip Sequential
· Reorg or not reorg? Defrag or not defrag ? Compress or not compress? are the questions..
· Functions coming before the I/O operation:
o HCD
o Power on Reset (POR)
o IPL
· Functions required by the Application code:
o allocate and unallocated the data set
o Open and Close the data set
o Invoke the Access Method via Read ou Write (just a branch).
· Access method functions:
o Buffering
o Blocking
o Write the channel program made of CCWs, (FICON) or TCW (zHPF)
o Síncronization
· I/O Drivers (Media Manager)
o Page fixing - DB2/VSAM Bufferpool page fixing.
o Translating the channel program (from virtual to real) adding MIDAW and TIDAW..
· Input Output Supervisor (IOS)
o UCBs e HyperPAV
o Device number, Subchannel number e Device Address
o IOSQ Time
o I/O Priority queueing e SAP I/O Priority (WLM IRD)
o SSCH instruction and UCWs (Concept of Subchannel Sets)
o I/O interrupts (z13 I/O Interrupt Delay time)
o CPU Enablement algorithm
o Serialization: Device Reserve CCW and GRS
o z/OS IECIOSxx (MIH e Hot I/O) member
· SAPs
o Master and Slave SAPs
o Initiative queue
o Pending Time
o SAP I/O RMF report and DASD I/O RMF report
o STP processing
· FICON Channels
o z13 PCIe Drawer
o FICON Architecture and FICON Express 16S
o Logical Channel Subsystem and Subchannel Sets
o CHPID and PCHID
o Channel to Channel Adapter (CTCA)
o zHPF
o I/O Connect e I/O Disconnect Time (causes of)
o FICON Director (Switch) - Buffer Credits and Multiplexing
o Logical Channel Subsystem (up to 6 in z13)
o WLM IRD Dynamic Channel Path Management
· DASD performance metrics:
o Average I/O Response Time and I/O Rate
o Channel efficiency
o Saturation point (and curve)
o DASD Traffic
o DASD Intensity
o CPU/DASD I/O Rate (RIOC)
· DASD Response Time and how to reduce each piece:
o IOSQ time
o Pending time and its subset CMR Time
o Connect time
o Disconnect time
o I/O Interrupt queue time
o I/O Delays and I/O Using in RMF and WLM
· DS888X
o Internal Design (I/O enclosures, Power RISC Processors, internal connections)
o DASD cache concepts and algorithms
o Real disk performance and availability aspects
o Logical and physical disks (hot spots) and Easy Tier
o RAID, capacity and RPM
o Heterogeneous Arrays/ranks
o Remote Copy Details and Flash Copy
o Logical Path and Logical Control Unit concepts
o Control unit I/O Priority and IOPM
o Multiple Allegiance
o Extended Addressing Volume (EAV)
o zHyperwrite
o Magnetic and SSD Devices
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