How relative do raw device bind block device on linux ?

How relative do raw device bind block device on linux ?

Post by Taekyu, Kw » Thu, 04 Apr 2002 20:49:15



Hello!!!
I tested  block i/o speed. when i tested file i/o speed,
i/o speed was 17mb/sec.
At this point file size was 3.1Gb, and command was "time dd
if=/linux_tag/linux.dd of=/linux_tag/linux_file.dd bs=8192k".
but when i tested block i/o speed, i/o speed was about 3mb/sec.
command was "time dd if=/dev/sdd1 of=/linux_tag/linux1.dd bs=8192k"

last i binded block device to raw device. and i test raw device i/o
speed.
command was "time dd if=/dev/raw/raw1 of=/linux_tag/linux_raw.dd
bs=8192k"
i/o speed was about 10Mb/sec.

why i/o speed was different between block device and raw device?

Please anyone explain to me!!!!!

Thank U.

 
 
 

1. How relative do raw device bind block device on linux ?

Hello!!!
I tested  block i/o speed. when i tested file i/o speed,
i/o speed was 17mb/sec.
At this point file size was 3.1Gb, and command was "time dd
if=/linux_tag/linux.dd of=/linux_tag/linux_file.dd bs=8192k".
but when i tested block i/o speed, i/o speed was about 3mb/sec.
command was "time dd if=/dev/sdd1 of=/linux_tag/linux1.dd bs=8192k"

last i binded block device to raw device. and i test raw device i/o
speed.
command was "time dd if=/dev/raw/raw1 of=/linux_tag/linux_raw.dd
bs=8192k"
i/o speed was about 10Mb/sec.

why i/o speed was different between block device and raw device?

Please anyone explain to me!!!!!

Thank U.

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