blk_limits_io_opt(9) [suse man page]

BLK_LIMITS_IO_OPT(9)						   Block Devices					      BLK_LIMITS_IO_OPT(9)

NAME

       blk_limits_io_opt - set optimal request size for a device

SYNOPSIS

       void blk_limits_io_opt(struct queue_limits * limits, unsigned int opt);

ARGUMENTS

       limits
	   the queue limits

       opt
	   smallest I/O size in bytes

DESCRIPTION

       Storage devices may report an optimal I/O size, which is the device's preferred unit for sustained I/O. This is rarely reported for disk
       drives. For RAID arrays it is usually the stripe width or the internal track size. A properly aligned multiple of optimal_io_size is the
       preferred request size for workloads where sustained throughput is desired.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010						      BLK_LIMITS_IO_OPT(9)

disktab(5)							File Formats Manual							disktab(5)

Name
       disktab - disk description file

Syntax
       #include <disktab.h>

Description
       The file is a simple data base that describes disk geometries and disk partition characteristics.  The format is patterned after the termi-
       nal data base.  Entries in consist of a number of fields separated by colons (:).  The first entry for each disk gives the names  that  are
       known for the disk, separated by vertical bars (|).  The last name given should be a long name fully identifying the disk.

       The following list indicates the normal values stored for each disk entry:
       Name Type Description
       ns   num  Number of sectors per track
       nt   num  Number of tracks per cylinder
       nc   num  Total number of cylinders on the disk
       ba   num  Block size for partition `a' (bytes)
       bd   num  Block size for partition `d' (bytes)
       be   num  Block size for partition `e' (bytes)
       bf   num  Block size for partition `f' (bytes)
       bg   num  Block size for partition `g' (bytes)
       bh   num  Block size for partition `h' (bytes)
       fa   num  Fragment size for partition `a' (bytes)
       fd   num  Fragment size for partition `d' (bytes)
       fe   num  Fragment size for partition `e' (bytes)
       ff   num  Fragment size for partition `f' (bytes)
       fg   num  Fragment size for partition `g' (bytes)
       fh   num  Fragment size for partition `h' (bytes)
       pa   num  Size of partition `a' in sectors
       pb   num  Size of partition `b' in sectors
       pc   num  Size of partition `c' in sectors
       pd   num  Size of partition `d' in sectors
       pe   num  Size of partition `e' in sectors
       pf   num  Size of partition `f' in sectors
       pg   num  Size of partition `g' in sectors
       ph   num  Size of partition `h' in sectors
       se   num  Sector size in bytes
       ty   str  Type of disk (e.g. removable, winchester)

       The entries can be automatically generated with the program.

Files
See Also
       chpt(8), newfs(8)

																	disktab(5)