ADSM-L

Prompted vs. Polling

2003-12-22 10:28:23
Subject: Prompted vs. Polling
From: Nancy Reeves <Nancy.Reeves AT WICHITA DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Mon, 22 Dec 2003 09:27:53 -0600
I'm trying to gather some statistics on how long scheduled backups take
and have discovered that things seem to be reported differently for
clients that are polling vs. prompted. I understand that with polling, the
schedule randomization percentage is used, and with prompted the server
contacts all nodes associated with a particular schedule at the same time
(within a couple of minutes).

A "q ev" gives me this for a prompted node.
  Scheduled Start: 12/19/03 03:00:00
  Actual Start: 12/19/03 04:28:01
  Completed: 12/19/03 04:28:04

And the activity log has these messages for that node. So it appears that
the Actual Start in the "q ev" is just for the session of writing the
stats.

12/19/03 03:00:12     ANR2561I Schedule prompter contacting BXXXXX
(session
                       11625) to start a scheduled operation.
12/19/03 03:00:17     ANR0406I Session 11636 started for node BXXXXX
(WinNT)
                       (Tcp/Ip 156.26.xxx.xxx(4710)).
... various 'file in use' messages
12/19/03 04:28:01     ANR0406I Session 11745 started for node BXXXXX
(WinNT)
                       (Tcp/Ip 156.26.xxx.xxx(2328)).
12/19/03 04:28:04     ANE4964I (Session: 11745, Node: BXXXXX)  Elapsed
                       processing time:            01:27:44

For a polling node, I don't get the ANR2561I message.  This example has a
12:00 scheduled start.

12/18/03 12:11:55     ANR0406I Session 10983 started for node RXXXXX
(WinNT)
                       (Tcp/Ip 156.26.xxx.xxx(3714)).
12/18/03 12:12:56     ANR0406I Session 10984 started for node RXXXXX
(WinNT)
                       (Tcp/Ip 156.26.xxx.xxx(3715)).
... various 'file in use' messages
12/18/03 12:25:16     ANR0403I Session 10984 ended for node RXXXXX
(WinNT).
12/18/03 12:25:17     ANE4964I (Session: 10983, Node: RXXXXX)  Elapsed
                       processing time:            00:13:20

The "q ev" commands gives an Actual Start time that matches the activity
log.
  Scheduled Start: 12/18/03 12:00:00
  Actual Start: 12/18/03 12:11:55
  Completed: 12/18/03 12:25:17


My questions for you all are:
How do you check stats for scheduled backup durations?
What are some reasons for choosing polling vs. prompted?

Thanks for the input.


Nancy Reeves
Technical Support, Wichita State University
Nancy.Reeves AT wichita DOT edu          316-978-3860

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