Rdist to keep a spare server up and running

[Phillip Popp]

Hi,
I really need some expert help. I am running 10.2 I have two machines. I want to use Rdist on a cron job to keep the second one updated to the first. If the first ever goes down, I can just changee the name and IP address on the second one and I am back in business. I made a recovery tape of the first machine and loaded it onto the second machine.
Problem is that the first machine has an extra 4 Gig disk and the second machine does not. The extra disk on the source machine only has one directory on it. So what I did was use one of the drives on the second machine and put the directory under there. It won't matter to the clients that need to access the machine, as long as they see the directory that will work. My problem comes when I do an Rdist to keep the machines the same. I was going to do Rdist /*, but if I do that it won't see that third drive on the second machine and throw an error. I can do an except and eliminate the files that are associated with the third drive configuration, but I have no idea which files that would entail. I have software that has critical files that update, in var and opt, so I need to Rdist them.
I though I could get away with the machines being fairly similar but not exact. They are the same model and size disks except for the extra one in the first machine. Any ideas? I would prefer not to bring the first machine down, as it will cause manufacturing to come down.

Hope I explained my self well enough.

Thanks,

Phil

[TwoProc]

Phil, as cheap as used HP 4G disks are, why not just put one in there? They probably cost all of $50 or so, plus shipping - and that is waaay overpriced (but used dealers want to make some $$ on old stuff too).

Since it appears that you are "rdisting" the whole machine - I don't see much of a choice to make that work. My only other suggestion would be just to sync up the application areas and leave the server configuration (/etc,/opt,/var,/tmp,/usr all of hpux sytem areas)alone - heck, it's not like your going to get a patch or something coming your way anytime soon on a 10.20 machine. Any other changes you make would remain in the /etc/passwd file (add/delete a user), /home directories, and whereever you put the application that you're running from. The rest of the machine should be VERY stagnant, right?

[TwoProc]

Phil, as cheap as used HP 4G disks are, why not just put one in there? They probably cost all of $50 or so, plus shipping - and that is waaay overpriced (but used dealers want to make some $$ on old stuff too).

Since it appears that you are "rdisting" the whole machine - I don't see much of a choice to make that work. My only other suggestion would be just to sync up the application areas and leave the server configuration (/etc,/opt,/var,/tmp,/usr all of hpux sytem areas)alone - heck, it's not like you're going to get a patch or something coming your way anytime soon on a 10.20 machine. Any other changes you make would remain in the /etc/passwd file (add/delete a user), /home directories, and whereever you put the application that you're running from. The rest of the machine should be VERY stagnant, right?

[OldSchool]

"I was going to do Rdist /*, but if I do that it won't see that third drive on the second machine and throw an error. "

I'm not sure that is a correct assumtion. I *believe* as long as rdist sees the correct directory path, it won't care how many physical drives are in place....

[Florian Heigl (new acc)]

Please use rsync instead of rdist!

- it will only transfer updates
- it will reliably notice updates
- it will allow you to skip the things you don't want transferred easily

You should be ok by skipping:
-Networking:
/etc/hosts
/etc/rc.config.d/netconf
/etc/rc.config.d/hpbtlanconf (substitute the correct file here)
-LVM config:
/etc/lvmconf/
/etc/lvmtab
/etc/fstab
-H/W paths:
/etc/ioconfig

and also, the root crontab :)

[Gilles Allard]

I would also recommend rsync instead of rdist. It is much more flexible.
Getting rsync for HP-UX 10.20 is not trivial. The source code is available from:
http://rsync.samba.org
and you should compile it using gcc.
You can also get a pre-compiled version from:
http://www.TheWrittenWord.com/

[Phillip Popp]

Thanks for all the ideas.

What about just moving the one directory on the first machine to another disk on the first machine, and set up it's own LV like it is now. Then unmount the extra 4 gig drive? That way they both would have the same config. One question though, would I need to remake a tape recovery of the first machine then reinstall on the second machine again, or could I just unmount the disk and set up a new lv, then Rdist.

Thanks,

Phil