© 2006 EMC Corporation. All rights reserved. The Host Environment Module 2.1

© 2006 EMC Corporation. All rights reserved. The Host Environment - 2 The Host Environment Upon completion of this module, you will be able to:  List the hardware and software components of the host environment  Describe key protocols and concepts used by each component

© 2006 EMC Corporation. All rights reserved. The Host Environment - 3 Examples of Hosts Laptop Server Group of Servers Mainframe

© 2006 EMC Corporation. All rights reserved. The Host Environment - 4 Host Physical Components Bus I/O Devices CPU Storage

© 2006 EMC Corporation. All rights reserved. The Host Environment - 5 CPU Bus ALU Registers L1 Cache

© 2006 EMC Corporation. All rights reserved. The Host Environment - 6 Storage … n Data 0 Data n Data 2 Data 3 Data 1 AddressContent Disk Memory

© 2006 EMC Corporation. All rights reserved. The Host Environment - 7 Storage Hierarchy – Speed and Cost Speed Slow Fast Cost HighLow Tape Optical disk Magnetic disk RAM L2 cache L1 cache CPU registers

© 2006 EMC Corporation. All rights reserved. The Host Environment - 8 I/O Devices  Human interface – Keyboard – Mouse – Monitor  Computer-computer interface – Network Interface Card (NIC)  Computer-peripheral interface – USB (Universal Serial Bus) port – Host Bus Adapter (HBA)

© 2006 EMC Corporation. All rights reserved. The Host Environment - 9 Host Environment: Logical Components

© 2006 EMC Corporation. All rights reserved. The Host Environment - 10 File Systems

© 2006 EMC Corporation. All rights reserved. The Host Environment - 11 File System: Metadata Examples UNIX (UFS)  File type and permissions  Number of links  Owner and group IDs  Number of bytes in the file  Last file access  Last file modification Windows (NTFS)  Time stamp and link count  File name  Access rights  File data  Index information  Volume information

© 2006 EMC Corporation. All rights reserved. The Host Environment - 12 File Systems: Journaling and Logging  Improves data integrity and system restart time over non-journaling file systems.  Uses a separate area called a log or journal. – May hold all data to be written – May hold only metadata  Disadvantage - slower than other file systems. – Each file system update requires at least 1 extra write – to the log

© 2006 EMC Corporation. All rights reserved. The Host Environment - 13 Volume Management

© 2006 EMC Corporation. All rights reserved. The Host Environment - 14 HBAs

© 2006 EMC Corporation. All rights reserved. The Host Environment - 15 Improving Data Availability at the Host Redundancy:  Multiple HBAs  Multi-pathing software  Clustering

© 2006 EMC Corporation. All rights reserved. The Host Environment - 16 How Files are Moved to and from Storage Teacher Configures / Manages File System Files Mapped by file system to Course File(s) Reside in File System Blocks Disk Physical Extents Consisting of LVM Logical Extents Residing in Mapped by LVM to Disk Sectors Managed by Disk Storage Subsystem

© 2006 EMC Corporation. All rights reserved. The Host Environment - 17 Module Summary Key points covered in this module:  Hosts typically have: – Hardware: CPU, memory, buses, disks, ports, and interfaces. – Software: applications, operating systems, file systems, device drivers, volume managers  HBAs connect hosts to storage devices.  Multi-pathing software uses redundant paths to ensure uninterrupted communication between the host and the storage  Clustering uses redundant host systems to improve data availability

© 2006 EMC Corporation. All rights reserved. The Host Environment - 18 Check Your Knowledge  What are some examples of hosts?  Describe the hardware components found in most hosts.  What is the function of the operating system?  What is the function of the file system?  What are some techniques that can be used to improve availability at the host?  What is volume management?