iotop for iSCSI or zfs datasets

[Alan Somers]

On Fri, Dec 7, 2018 at 6:09 AM Eugene M. Zheganin <eugene at zhegan.in> wrote:
>
> Hello,
>
>
> I have several iSCSI SAN systems running FreeBSD, and I need a tool to
> quickly determine which target/targets (and thus which initiator) are
> consuming most of iops. I can see that there are cfiscsi/iscsi probes in
> the FDT provider, and lots of zfs probes. Since my targets are using
> zvols as backends, both types will fir. I have some basic skills with
> dtrace, but in this case I totally lack documentation, so could you
> please point me to a direction (I'm not quite good at reading sources,
> but if that's the only way - you could point me to a specific part of
> the FreeBSD source tree I guess) to find the answer to a question "where
> can I find which probes/functions can I use to gather this data,
> including the argument list/types for them?"
>
> I was made aware that there's a ctlstat(8) utility, but it's not handy
> when it comes to hundreds of LUNs.
>
> I also can see the iotop in the context of network data transferred
> using trafshow, but this doesn't scale well to iops, and I would see
> reads/writes per second in terms that block devices use.
>
>
> Thanks.
>
> Eugene.

What's wrong with gstat?  Use "gstat -a" to suppress idle devices.
-Alan