On Wed, May 31, 2006 at 12:26:55AM +0200, Robert Milkowski wrote:
> Hello zfs-discuss,
>
> I noticed on a nfs server with ZFS that even with atime set to off
> and clients only reading data (almost 100% reads - except some
> unlinks()) I still can see some MB/s being written according to
> zpool iostat. What could be the couse? How can I see what is
> actually being written by ZFS (what files, metadata, etc.)?
You may use my attached zfs_io.d dtrace script. This will tell you what
object numbers are being written. You can use zdb to determine the file
names from that. Obviously, this is a kludge and any real solution
would tell you the file names directly.
--matt
#!/usr/sbin/dtrace -qs
zio_done:entry
/args[0]->io_type == 1 && args[0]->io_bp != NULL/
{
@bytes["read",
args[0]->io_bookmark.zb_objset,
args[0]->io_bookmark.zb_object,
args[0]->io_bookmark.zb_level,
args[0]->io_bookmark.zb_blkid != 0] =
/* sum(args[0]->io_size); */
count();
}
zio_done:entry
/args[0]->io_type == 2/
{
@bytes["write",
args[0]->io_bookmark.zb_objset,
args[0]->io_bookmark.zb_object,
args[0]->io_bookmark.zb_level,
args[0]->io_bookmark.zb_blkid != 0] =
/* sum(args[0]->io_size); */
count();
}
END
{
printf("r/w objset object level blk>0 i/os\n");
printa("%5s %4d %7d %d %d [EMAIL PROTECTED]", @bytes);
printf("r/w objset object level blk>0 i/os\n");
}
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