Rolling back the years

Rolling back the years

Post by Tom Whale » Wed, 03 Mar 1999 04:00:00



There's a ongoing feud happening in my organization and would like to
present it to this group for analysis.  The feud is the issue of rolling
back the dates in HP-UX.  As I believe that it's necessary to roll back the
clock on the HP-UX machines we have on 10.20.43, I also think there is
considerable damage that could occurr when you come back to reality.  Things
like file datestamping, etc.  What's everyone's take on this???

--
Tom Whalen
Data Center Manager
Community Health Care, Inc.

                 > T h e  T r u t h  i s  O u t  T h e r e  <

 
 
 

Rolling back the years

Post by Darren & Felici » Thu, 04 Mar 1999 04:00:00


Be careful when you roll back to pick a year where the days of the week
fall the same.  This will be especially difficult since 2000 is a leap year!
If you don't things like cron will be outa-wack.


>There's a ongoing feud happening in my organization and would like to
>present it to this group for analysis.  The feud is the issue of rolling
>back the dates in HP-UX.  As I believe that it's necessary to roll back the
>clock on the HP-UX machines we have on 10.20.43, I also think there is
>considerable damage that could occurr when you come back to reality.
Things
>like file datestamping, etc.  What's everyone's take on this???

>--
>Tom Whalen
>Data Center Manager
>Community Health Care, Inc.

>                 > T h e  T r u t h  i s  O u t  T h e r e  <


 
 
 

Rolling back the years

Post by Solomon Red » Thu, 04 Mar 1999 04:00:00


We have actually changed the system time on our year 2000 test server back
and forth to test different scenarios and what I found out is that when you
move forward by more than a day, cron and at get a little confused and jobs
that you did not expect will to get fired off. Moving backwards is a lot
worse, if you have any applications/jobs that depend on file timestamps then
the effect of this change is unpredictable. If you run a database server
then you ran the risk of corrupting all your database (specially Oracle
databases!!).

If you plan to roll the clock back for a test then make sure you have a good
backup, bring down all applications and databases, stop cron, change the
time, restart cron. You will probably have to recreate and reload your
databases from backup ......


>There's a ongoing feud happening in my organization and would like to
>present it to this group for analysis.  The feud is the issue of rolling
>back the dates in HP-UX.  As I believe that it's necessary to roll back the
>clock on the HP-UX machines we have on 10.20.43, I also think there is
>considerable damage that could occurr when you come back to reality.
Things
>like file datestamping, etc.  What's everyone's take on this???

>--
>Tom Whalen
>Data Center Manager
>Community Health Care, Inc.

>                 > T h e  T r u t h  i s  O u t  T h e r e  <

 
 
 

Rolling back the years

Post by Steve Holdow » Fri, 05 Mar 1999 04:00:00




Quote:>There's a ongoing feud happening in my organization and would like to
>present it to this group for analysis.  The feud is the issue of rolling
>back the dates in HP-UX.  As I believe that it's necessary to roll back the
>clock on the HP-UX machines we have on 10.20.43, I also think there is
>considerable damage that could occurr when you come back to reality.  Things
>like file datestamping, etc.  What's everyone's take on this???

Well, with a subject line like this, you must remember the 70's, so
what's the problem! My bottom line is this... if you change the date,
then it's worth waiting the extra 15 minutes while the system
reboots.. especially when you're goin' back to the dark ages when
Steely Dan were in every cafe, and Donald Fagen was a minor deity!

That way HP-UX knows that time may not be consistent, and sorts itself
out. It's pretty cool about files that haven't been created yet.

No sweat!

Steve

 
 
 

Rolling back the years

Post by Yves Dorfsma » Tue, 09 Mar 1999 04:00:00



> the effect of this change is unpredictable. If you run a database server
> then you ran the risk of corrupting all your database (specially Oracle
> databases!!).

We do, we haven't had any problem so far.

Quote:> If you plan to roll the clock back for a test then make sure you have a good
> backup, bring down all applications and databases, stop cron, change the
> time, restart cron. You will probably have to recreate and reload your
> databases from backup ......

What I do to roll back is:
-take the machine in Single user mode (we have all the apropriate rc
files which shut down all the apps).
-change the clock back
-  touch /tmp/now
   find / -newer /tmp/now -exec touch {} \;
(This doesn't work for links though).

-Reboot the machine.

Yves.
----

                                         http://www.cuug.ab.ca/~dorfsmay

 
 
 

Rolling back the years

Post by Ulrich Win » Wed, 10 Mar 1999 04:00:00




> > the effect of this change is unpredictable. If you run a database server
> > then you ran the risk of corrupting all your database (specially Oracle
> > databases!!).

> We do, we haven't had any problem so far.

> > If you plan to roll the clock back for a test then make sure you have a good
> > backup, bring down all applications and databases, stop cron, change the
> > time, restart cron. You will probably have to recreate and reload your
> > databases from backup ......

> What I do to roll back is:
> -take the machine in Single user mode (we have all the apropriate rc
> files which shut down all the apps).
> -change the clock back
> -  touch /tmp/now
>    find / -newer /tmp/now -exec touch {} \;

Wouldn't "find / -newer /tmp/now -print | xargs touch" be more efficient?

Ulrich

 
 
 

1. Setting year back to 1978 in HPUX.

Good Morning,

Some management types here want to set the year back to 1978, which they
are told has the same day of year/day of week as 2000. Has anybody tried
this with HPUX, we are also running Remedy and Oracle. I keep telling
them that they could have serious problems, but they want to save a few
bucks. What do you HP users have to say about it?

Thanks,
Vic
--
James V. Ryan   aka   Vic  !Communications Link Analysis & Simulation System
Code 450.J, Bldg. 25, N105C! AlliedSignal  Technical  Services  Corporation

Greenbelt, MD  20771       !Fax - Prime: 301-286-4672,  Backup: 301-286-1770

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