• Responsible
for creating and controlling host level logical storage
– Physical view of storage is converted to
a logical view by mapping
– Logical data blocks are mapped to
physical data blocks
• Usually
offered as part of the operating system or as third party host software
• LVM
Components:
– Physical Volumes
– Volume Groups
– Logical Volumes
Volume
Groups
•One
or more Physical Volumes form a Volume Group
•LVM
manages Volume Groups as a single entity
•Physical
Volumes can be added and removed from a Volume Group as necessary
•Physical
Volumes are typically divided into contiguous equal-sized disk blocks
•A
host will always have at least one disk group for the Operating System
–Application and Operating System data
maintained in separate volume groups
LVM
Example: Partitioning and Concatenation
Logical
Components of the Host (Cont)
•Device Drivers
–Enables
operating system to recognize the device
–Provides
API
to
access and control devices
–Hardware
dependent and operating system specific
•File System
–File
is a collection of related records or data stored as a unit
–File
system is hierarchical structure of files
•Examples:
FAT 32, NTFS, UNIX FS and EXT2/3
How
Files are Moved to and from Storage
