Time change on SP 1

[billy1]

The clocks will be going back an hour next week and subsequently we have to update our SP frame. I know I have to change the time on the SP CWS through smit first of all but would anybody know what the command is to push this time out to all other nodes ?

 

[columb]

On my SP system it all happens automaticaly - I'm using AIX 4.3.

Whilst on the subject, for those, like me six months ago, who didnt' know what happens during the changeover, the man page for cron gives

Note:

o If you have a job scheduled to run between 1:00 AM and 2:00 AM on the
day your time zone changes from daylight saving time to standard time
your job will run twice.
o If you have a job scheduled to run between 2:01 AM and 2:59 AM on the
day your time zone changes from standard time to day light savings time
your job will not run. You can change the time these jobs run, run them
manually, or with until the following day to run them. The cron daemon
does not need to be stopped. However, if changes are made to the TZ
environment variable, kill the current cron daemon so that it
automatically respawns and recognizes the new TZ setting.

i.e. anything between 01:00 and 02:00 will run twice.

Ceci n'est pas une signature
Columb Healy

 

[billy1]

Its not automatic on our SP frame so has to be done manually. I presume the 'dsh' command is used somehow ?

 

[Breslau]

we have ntp set up on all our nodes, they point to a single server on our campus that coords their time.

to do it manually, you could use dsh as you said,

dsh -a <date command with options>

this would shell out to all your nodes and run the command(s) you want.

maybe there's a way to do this thru smit, but i have never used it. ntp is much more simple to maintain.

 

[kHz]

You should be using NTP on your SP complex because of Kerberos. All you should have to do is make sure the time is correct on the timeserver.

Otherwise, as said, use dsh.

 

[p5wizard]

We never touch the clocks, it's all done with the time zone parameter.

A unix server's clock should IMHO always run in GMT or CUT. For western europe, the TZ value

TZ=NFT-1DFT,M3.5.0/2:00:00,M10.5.0/3:00:00

will alter the displaying of the time to match WE daylight savings time. In winter, 1 hour ahead of GMT, in summer (last sunday of March at 2 am until last sunday of October at 3am) 2 hours ahead of GMT.

NTP does not have anything to do with summer/winter time as that only synchronizes the CPU's GMT or CUT clocks.

You can use "smit chtz" to alter your server's TZ parameter, but if you do, then you should reboot the server or node, or at least stop/start cron so that it knows about the changed TZ value.


HTH,

p5wizard

 

[kHz]

The TZ depends on the level of AIX, too. There is a patch but if you are at 5300-04 you will be fine for the TZ.

 

[p5wizard]

I've used TZ like this since AIX433 (probably even earlier but my memory fails me right now)


HTH,

p5wizard

 

[billy1]

Thanks everyone. This will need to be done manually.
Breslau mentioned the dsh command
"dsh -a <date command with options>"
would anybody know what these options are ? I've looked up the man page for dsh and it's not specified. Also is this run from the CWS only and if so does each host (node) need to be specified ?

 

[Breslau]

dsh -a means run the following command on all my nodes.

dsh will take any command that you could run on a single machine as a parameter. for instance,

dsh -a date

run from the CWS will run the `date` command on all your nodes, and return the output from each one to your CWS.

to set the time you could,

dsh -a date 0217142590


For a system using CST as its time zone, this sets the date and time to Sat Feb 17 14:25:00 CST 1990. (on all nodes)

see the man page entry for the 'date' command to get all the gory details of what you need.

 

[billy1]

Excellent, thanks Breslau.