[blktrace 사용법]

Usage 1)

blktrace /dev/sda /dev/sdc &

kill -15 pid

blkparse sda sdc > events

less events

 

 

 

Usage 2)

화면에서 실시간 확인시

blktrace [블록장치경로] -a complete -o - | blkparse -f “%d,%S,%n\n” -i -

 

Usage 3)

파일로 저장시

blktrace [블록장치경로] -a complete

blkparse -f “%d,%S,%n\n”-i [tracefile] > test.csv

 

 -f Output format. Customize the output format. The format field
   identifiers are:

%a - Action
%c - CPU ID
%C - Task command (process) name
%d - Direction (r/w)
%D - Device number
%e - Error number
%M - Major
%m - Minor
%N - Number of bytes
%n - Number of sectors
%p - PID
%P - PDU
%s - Sequence number
%S - Sector number
%t - Time (wallclock - nanoseconds)
%T - Time (wallclock - seconds)
%u - Time (processing - microseconds)
%U - Unplug depth

 

Default Output

The standard header (or initial fields displayed) include:

"%D %2c %8s %5T.%9t %5p %2a %3d"

Breaking this down:

%D

Displays the event's device major/minor as: %3d,%-3d.

%2c

CPU ID (2-character field).

%8s

Sequence number

%5T.%9t

5-character field for the seconds portion of the time stamp and a 9-character field for the nanoseconds in the time stamp.

%5p

5-character field for the process ID.

%2a

2-character field for one of the actions.

%3d

3-character field for the RWBS data.

Seeing this in action:

8,0 3 1 0.000000000 697 G W 223490 + 8 [kjournald]

The header is the data in this line up to the 223490 (starting block). The default output for all event types includes this header.

 

 

 

$ blktrace -d /dev/sda -o - | blkparse -i - /sys/kernel/debug does not apper to be a debug filesyste

위와 같은 에러를 내면서 blktrace가 동작하지 않는다면, 



아래와 같이 해 준다.

$ mount -t debugfs debugfs /sys/kernel/debug

 

To launch automatically,

put this into /etc/fstab

 

debug /sys/kernel/debug debugfs default 0 0

출처 : http://blog.naver.com/PostView.nhn?blogId=go4real&logNo=89718340&redirect=Dlog&widgetTypeCall=true