Hmmm....so coming back around to the problem we're trying to solve -
You have iostat data and "zpool iostat" data that shows a steady stream
of writes to one or more of your zpools, correct?
You wish to identify the source of those writes, correct?
Try saving this as a file and running it, and please run it in conjunction
with iostat or zpool iostat data, so we can determine what the disparity
is in what is being reported.
***** WARNING ******
I am NOT a ZFS expert. I'm fumbling my way around. I'm not sure if
my use of uio->resid in the script below is a reasonable way to answer
the "how many bytes of write IO am I generating" question. I'm still
chasing that.
-------------- zfsw.d ------------------------
#!/usr/sbin/dtrace -s
#pragma D option quiet
fbt:zfs:zfs_write:entry
{
@[execname,stringof(args[0]->v_path),args[1]->uio_resid] = count();
}
tick-1sec
{
printf("%-16s %-40s %-8s %-8s\n","EXEC","PATH","BYTES","COUNT");
printa("%-16s %-40s %-8d %-@8d\n",@);
trunc(@);
printf("\n");
}
tick-120sec
{
exit(0);
}
When this is executed in parallel with the other utilities that are reporting
writes, what do the numbers look like? What is the disparity in IOPS
and/or bytes being written?
On Jun 11, 2011, at 1:00 PM, Jim Klimov wrote:
> 2011-06-11 20:42, Jim Mauro пишет:
>> Well we may have missed something, because that dtrace will
>> only capture write(2) and pwrite(2) - whatever is generating the writes
>> may be using another interface (writev(2) for example).
>>
>> What about taking it down a layer:
>>
>> dtrace -n 'fsinfo:::write /args[0]->fi_fs == "zfs"/ {
>> @[execname,args[0]->fi_pathname] = count(); }'
>
> Seems similar (to my successful last run) - when I do
> something with the system, a few files are shown:
>
> # time dtrace -n 'fsinfo:::write /args[0]->fi_fs == "zfs"/ {
> @[execname,args[0]->fi_pathname] = count(); }'
> dtrace: description 'fsinfo:::write ' matched 1 probe
> ^C
>
> grep
> /var/svc/log/network-iscsi-target-dcpool:default.log 1
> fmd
> /etc/devices/snapshot_cache.tmp 2
> svc.startd
> /var/svc/log/network-iscsi-initiator-dcpool:default.log 3
> svc.startd
> /var/svc/log/network-iscsi-target-dcpool:default.log 3
> syslogd /var/adm/messages
> 7
> sbdadm
> /var/svc/log/network-iscsi-target-dcpool:default.log 22
> fmd
> /var/fm/fmd/infolog_hival 24
> Xvnc
> /root/.vnc/bofh-sol:64.log 93
> freeram-watchdog
> /var/log/freeram-watchdog.log.1307810438 104
> svc.configd /etc/svc/repository.db
> 232
> svc.configd
> /etc/svc/repository.db-journal 352
>
> real 1m45.585s
> user 0m1.439s
> sys 0m0.330s
>
>
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