Bug 117664
| Summary: | iostat can't display IO current vlaue in first line | ||
|---|---|---|---|
| Product: | Base System | Reporter: | chifeng |
| Component: | amd64 | Assignee: | freebsd-amd64 (Nobody) <amd64> |
| Status: | Closed FIXED | ||
| Severity: | Affects Only Me | ||
| Priority: | Normal | ||
| Version: | Unspecified | ||
| Hardware: | Any | ||
| OS: | Any | ||
On Tue, Oct 30, 2007 at 07:22:39AM +0000, chifeng wrote:
>When I write a shell script plugin for munin, I hope get a current value of IO statistics. But iostat can't do it, it first statistics that are printed are avaraged over the system uptime. If I use "iostat -c 2 | tail -1 " command, this will wait 2s at least.
>so I think for iostat first line, 1) iostat should be display current value, 2) have a parameter to display current value at least.
This is generic, rather than amd64-specific.
I believe you misunderstand iostat. There is no "current value" as
you desire. There are a variety of system counters that get updated
when various events occur and iostat reports the change in those
counters over the specified interval. The only way to determine the
system activity, averaged over two seconds, is to sample the counters,
wait two seconds, sample the counters again and reports the differences.
I suggest you start a thread on (eg) freebsd-questions explaining what
you are trying to achieve and someone there may be able to assist.
In the meantime, you might like to investigate the sysutils/bsdsar port.
--
Peter
On Tuesday 30 October 2007 03:22:39 am chifeng wrote: > > >Number: 117664 > >Category: amd64 > >Synopsis: iostat can't display IO current vlaue in first line > >Confidential: no > >Severity: non-critical > >Priority: low > >Responsible: freebsd-amd64 > >State: open > >Quarter: > >Keywords: > >Date-Required: > >Class: change-request > >Submitter-Id: current-users > >Arrival-Date: Tue Oct 30 07:30:02 UTC 2007 > >Closed-Date: > >Last-Modified: > >Originator: chifeng > >Release: FreeBSD6.2-Release-p8 > >Organization: > Platform Computing > >Environment: > FreeBSD cnxabuild.asia.corp.platform.com 6.2-RELEASE-p8 FreeBSD 6.2-RELEASE-p8 #0: Tue Oct 16 12:32:14 CST 2007 root@xabuild.asia.corp.platform.com:/usr/obj/usr/src/sys/PLATFORM amd64 > >Description: > When I write a shell script plugin for munin, I hope get a current value of IO statistics. But iostat can't do it, it first statistics that are printed are avaraged over the system uptime. If I use "iostat -c 2 | tail -1 " command, this will wait 2s at least. > so I think for iostat first line, 1) iostat should be display current value, 2) have a parameter to display current value at least. There isn't a 'current value' for iostat to dump. The kernel just keeps running counts and iostat simulates a current value by saving the values each time and computing a delta for each line after the first. However, for the first line there is no saved value so it cannot compute a delta. Probably you need to write your own plugin that saves the previous values and computes deltas when queried similar to how iostat behaves. -- John Baldwin State Changed From-To: open->closed As detailed in followup, this is just a property of the counters and the way iostat works. |
When I write a shell script plugin for munin, I hope get a current value of IO statistics. But iostat can't do it, it first statistics that are printed are avaraged over the system uptime. If I use "iostat -c 2 | tail -1 " command, this will wait 2s at least. so I think for iostat first line, 1) iostat should be display current value, 2) have a parameter to display current value at least. # iostat -c 5 tty ad2 cpu tin tout KB/t tps MB/s us ni sy in id 0 2 16.48 1 0.01 0 0 0 0 100 0 130 63.63 782 48.60 0 0 14 1 85 0 104 62.68 594 36.38 2 0 24 0 73 0 77 62.75 663 40.63 0 0 16 0 83 0 67 24.65 1568 37.76 0 0 18 1 80 # iostat tty ad2 cpu tin tout KB/t tps MB/s us ni sy in id 0 2 17.52 1 0.01 0 0 0 0 100 Fix: :-( I don't know how to fix it. How-To-Repeat: iostat command.