The Host Environment
Module 2.1
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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
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The Host Environment - 2
Examples of Hosts
Server
Laptop
Group of Servers
Mainframe
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The Host Environment - 3
Host Physical Components
CPU
Bus
Storage
I/O Devices
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The Host Environment - 4
CPU
Bus
ALU
L1 Cache
Bus
CPU
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Registers
The Host Environment - 5
Storage
…
n
Data n
3
Data 3
2
Data 2
1
Data 1
0
Data 0
Address
Content
Disk
Memory
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The Host Environment - 6
Storage Hierarchy – Speed and Cost
Fast
CPU registers
L2 cache
Speed
Magnetic
disk
Tape
L1 cache
RAM
Optical
disk
Slow
Low
High
Cost
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The Host Environment - 7
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)
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The Host Environment - 8
Host Environment: Logical Components
Host
Apps
Operating System
Mgmt Utilities
DBMS
File System
Volume Management
Multi-pathing Software
Device Drivers
HBA
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HBA
HBA
The Host Environment - 9
File Systems
Host
Apps
Operating System
Mgmt Utilities
DBMS
File System
Volume Management
Multi-pathing Software
Device Drivers
HBA
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HBA
HBA
The Host Environment - 10
File System: Metadata Examples
UNIX (UFS)
Windows (NTFS)
 File type and permissions
 Time stamp and link count
 Number of links
 File name
 Owner and group IDs
 Access rights
 Number of bytes in the file
 File data
 Last file access
 Index information
 Last file modification
 Volume information
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The Host Environment - 11
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
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The Host Environment - 12
Volume Management
Host
Apps
Operating System
Mgmt Utilities
DBMS
File System
Volume Management
Multi-pathing Software
Device Drivers
HBA
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HBA
HBA
The Host Environment - 13
HBAs
Host
Apps
Operating System
Mgmt Utilities
DBMS
File System
Volume Management
Multi-pathing Software
Device Drivers
HBA
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HBA
HBA
The Host Environment - 14
Improving Data Availability at the Host
Redundancy:
 Multiple HBAs
 Multi-pathing software
 Clustering
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The Host Environment - 15
How Files are Moved to and from Storage
Teacher
Course File(s)
Configures /
Manages
File System Files
Reside
in
Disk Sectors
Managed by
Disk Storage
Subsystem
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Mapped by
file system to
Disk Physical
Extents
Consisting
of
File System Blocks
LVM Logical
Extents
Mapped by
LVM to
Residing
in
The Host Environment - 16
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
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The Host Environment - 17
 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?
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The Host Environment - 18