nfsv4io.d Reports Host I/O

This is a simple DTrace script to provide basic I/O details by host every 5 seconds:

#!/usr/sbin/dtrace -s

#pragma D option quiet

dtrace:::BEGIN
{
        interval = 5;
        printf("Tracing... Interval %d secs.\n", interval);
        tick = interval;
}

nfsv4:::op-*
{
        @ops[args[0]->ci_remote] = count();
}

nfsv4:::op-read-done
{
        @reads[args[0]->ci_remote] = count();
        @readbytes[args[0]->ci_remote] = sum(args[2]->data_len);
}


nfsv4:::op-write-done
{
        @writes[args[0]->ci_remote] = count();
        @writebytes[args[0]->ci_remote] = sum(args[2]->count);
}

profile:::tick-1sec
/tick-- == 0/
{
        normalize(@ops, interval);
        normalize(@reads, interval);
        normalize(@writes, interval);
        normalize(@writebytes, 1024 * interval);
        normalize(@readbytes, 1024 * interval);
        printf("\n   %-32s %6s %6s %6s %6s %8s\n", "Client", "r/s", "w/s",
            "kr/s", "kw/s", "ops/s");
        printa("   %-32s %@6d %@6d %@6d %@6d %@8d\n", @reads, @writes,
            @readbytes, @writebytes, @ops);
        trunc(@ops);
        trunc(@reads);
        trunc(@writes);
        trunc(@readbytes);
        trunc(@writebytes);
        tick = interval;
}

This output shows 192.0.2.14 calling NFSv4 reads and writes:

# ./nfsv4io.d 
Tracing... Interval 5 secs.

   Client                            r/s    w/s   kr/s   kw/s    ops/s
   192.0.2.14                        17      1    331     40      290

   Client                            r/s    w/s   kr/s   kw/s    ops/s
   192.0.2.14                         9      0    197      0      152

   Client                            r/s    w/s   kr/s   kw/s    ops/s
   192.0.2.14                        16      0    269      0      363

   Client                            r/s    w/s   kr/s   kw/s    ops/s
^C

Other details can be calculated from the output, such as average read and write size, for example 331(kr/s) / 17(r/s) = 19.5 average kr. These could also be added to the script to be printed as columns.

The fields printed are:

Field	Description
Client	Remote client IP address
r/s	Reads per second
w/s	Writes per second
kr/s	Kbytes read per second
kw/s	Kbytes written per second
ops/s	Total NFSv4 operations per second (including the reads and writes)