dtrace discuss - Dec 2008 - iosnoop doesn''t report IO activity for dd

Hi, All,

root at haozhuhost-/export/home/oracle/qihua/DTraceToolkit-0.99/Bin>  dd
bs=16384 if=/oracle/hao/data01/data01_01.dbf of=/tmp/test1 &
[1] 1904
root at haozhuhost-/export/home/oracle/qihua/DTraceToolkit-0.99/Bin>
./iosnoop
-f /tmp/test1
  UID   PID D    BLOCK   SIZE       COMM PATHNAME
20800+1 records
in
===> *didn''t report the IO activity on file /tmp/test1. is it
correct?*
20800+1 records out
^C

[1]+  Done                    dd bs=16384
if=/oracle/hao/data01/data01_01.dbf of=/tmp/test1


Thanks,
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/tmp is almost certainly a memory based file system. iosnoop captures
only physical disk IOs which a memory based file system does not do.

Jim
---

Qihua Wu wrote:
> Hi, All,
>
> root at haozhuhost-/export/home/
> oracle/qihua/DTraceToolkit-0.99/Bin>  dd bs=16384 
> if=/oracle/hao/data01/data01_01.dbf of=/tmp/test1 &
> [1] 1904
> root at haozhuhost-/export/home/oracle/qihua/DTraceToolkit-0.99/Bin> 
> ./iosnoop -f /tmp/test1
>   UID   PID D    BLOCK   SIZE       COMM PATHNAME
> 20800+1 records 
> in
> ===> *didn''t report the IO activity on file /tmp/test1. is it
correct?*
> 20800+1 records out
> ^C
>
> [1]+  Done                    dd bs=16384 
> if=/oracle/hao/data01/data01_01.dbf of=/tmp/test1
>
>
> Thanks,
> ------------------------------------------------------------------------
>
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