[dtrace-discuss] File name not being displayed.

Pramod Batni
2009-08-16T21:38:00Z

James Litchfield wrote:
> I''ve never seen the file name when doing this with ZFS.
> My belief is that ZFS will cheerfully bundle a bunch of data
> together from disparate files and spit it out to disk. It''s done
> with taskq threads so you can''t tie the IO to a specific process.
> For ZFS, this just doesn''t work.
>
> Jim
> ----

 Thanks Jim.


>
> Pramod Batni wrote:
>> vhiz wrote:
>>> Hi Pramod,
>>>
>>>                      I am using the ZFS filesystem on OpenSolaris.
>>> The thing is that the file that my program is reading is 2.5 GB in
>>> size, which is greater than the RAM size. Will caching still take
>>> place? And when I run the script, I can see that the number of
reads
>>> that it displays goes up quite a bit. So the reads are being
>>> captured, just that the file name is not being displayed.
>>>
>>>
>>
>> I suspect {need to verify} that reading in the large file [more than
>> the RAM size] is blowing out the v_path information from the vnode.
 Apologies. The  previous statement is incorrect.
 As Jim mentions, the file name does not show up when doing IO to files
on ZFS.
 I just checked it out on a system and yes the script does not give the
name of the ZFS file which is
 read/written to disk. The IO''s are handled via zio''s and
there appears
to be no linkage from the zio to the vnode [where
 the name is stored]
 On a side note, the script does work for files residing on UFS.

Pramod