topic Re: Resetting System Date in Operating System - HP-UX

Resetting System Date

Roger Lavender — Tue, 31 Aug 2004 06:15:57 GMT

For various reasons, I have a server which is living in the future and I need to bring it back to the present - kind of a time warp thing, I won't go into details how it got that way.

Besides the various database implications involved with a date roll-back, and that I'll need to bring the server into single user mode to change the date, what other implications should I be looking at before I roll the date back.

Thanks in advance.

Re: Resetting System Date

Pete Randall — Tue, 31 Aug 2004 06:18:21 GMT

Roger,

The database is the big one. Other than that, you shouldn't really have to worry. How far in the future is this server (and how did it get that way?)? Can you leave it down long enough that you won't have to worry about the dates overlapping?

Pete

Re: Resetting System Date

Roger Lavender — Tue, 31 Aug 2004 06:30:03 GMT

Well Pete, a DBA set the date into the future - late October to be exact, because they wanted to test some fiscal year stuff. The server is a development, not production setup. I think shutting it down for two months might be a bit much.

Of course, on the bright side, I've got 2 new rp7420's coming - one of which replaces this server.

Re: Resetting System Date

Cheryl Griffin — Tue, 31 Aug 2004 06:33:54 GMT

System files that have future dates can cause problems if you roll the date back.

You should do a search for future dates and once the time has been reset to the current date, touch all the files you found with future dates.

This still won't affect entries within some system files that have the date recorded, which can continue to cause you problems, such as /etc/wtmp (btmp, utmp), etc.

And such, if you experience weird errors down the road, you need to keep in mind that rolling back a date can certainly be the culprit.

Re: Resetting System Date

Pete Randall — Tue, 31 Aug 2004 06:37:26 GMT

You're definitely right, Roger: two months is just a bit too long!

Since it's development and not production, I'd be a lot less concerned about the DB issues. The problem would show up if you had to roll back a transaction using the logs. If you don't have to roll anything back, then there shouldn't be any issues.

We did a similar thing back when we were testing Y2K preparations and managed to recover from it without issue.

Good luck!

Pete

Re: Resetting System Date

Tom Danzig — Tue, 31 Aug 2004 07:15:43 GMT

I would suggest using the "date -a" command. This will slowly adjust the clock to the correct time and should have minimal impact on the DB. See man date.

Re: Resetting System Date

Jeroen Peereboom — Tue, 31 Aug 2004 07:22:01 GMT

I would expect some issues with backup software. Files not being backed up because they're older than the version on the full back-up, or files being backed up on each incremental / differential backup....

JP.

Re: Resetting System Date

Geoff Wild — Tue, 31 Aug 2004 08:14:00 GMT

You may also have issues with onlinejfs - we moved a server 8 months a head to test a year end - when we moved it back, the vxlicense was corrupt - had to re-install online jfs...

Rgds...Geoff

Re: Resetting System Date

Cheryl Griffin — Tue, 31 Aug 2004 08:53:49 GMT

During Y2K, the Response Center was telling everyone to back up your system prior to rolling the date forward and back because otherwise the system would be in an unsupported state.

There is not a comprehensive list of potential problems because it would be impossible to cover every software and system configuration scenario.

It was a blanket: unsupported.

Re: Resetting System Date

A. Clay Stephenson — Tue, 31 Aug 2004 09:02:51 GMT

Because you indicate that this is a development box, another "gotcha" is timestamps of source and object files and make files. The "make" utility depends very heavily upon accurate timestamps of the source files and the object files generated. For example, suppose that a given executable, my.exe depends upon 2 object files: my.o and my2.o. My.o and my2.o depend in turn upon the "c" source files my.c and my2.c. Makes looks at the timestamps and if the ".c" files are newer than the ".o" files, it needs to take some action (e.g. invoke the compiler). In your case, you could update the source files and because the source files now appear OLDER than the ojects nothing will be done. I use use as an example but the same can apply to scripts, Pro*C, forms, or other files.

Re: Resetting System Date

Matthew Hollier — Tue, 31 Aug 2004 09:37:41 GMT

Worth checking for jobs that run from cron or a batch scheduler (if you have one). By changing the dates you may find that jobs run again, or won't run until it gets back to the future date.

Re: Resetting System Date

Roger Lavender — Tue, 31 Aug 2004 11:00:21 GMT

No onlinejfs so that's not a worry.
Yep, I remember the HP Solution for Y2K.
Checked the backups - full taken just prior to the date change.
Trusted Security files are an issue - but only for me.
No application cronjobs so that makes things alittle easier.
No programming on this server so don't have to worry about source/object compile issues.
I have a list of all the files affect now.

Thanks for eveyone suggestions.
Roger

Re: Resetting System Date

Roger Lavender — Tue, 31 Aug 2004 11:01:05 GMT

Closed.