[dtrace-discuss] File name not being displayed.

James Litchfield
2009-08-16T21:10:34Z

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
----

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.
>>
>>
> So you see <unknown> instead of the name of the file ?
>
> Notice that your script is using fi_pathname to print the pathname of
> the file which is undergoing IO.
>> From
''http://wikis.sun.com/display/DTrace/io+Provider''
> --snip--
> The fi_name field contains the name of the file but does not include
> any directory components. If no file information is associated with an
> I/O, the fi_name field will be set to the string <none>. In some rare
> cases, the pathname associated with a file might be unknown. In this
> case, the fi_name field will be set to the string <unknown>.
> The fi_pathname field contains the full pathname to the file. As with
> fi_name, this string may be set to <none> if no file information is
> present, or <unknown> if the pathname associated with the file is not
> known.
> --snip--
> 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.
>
> Pramod
>
>> Thanks.
>>
>
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