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Top Down Rebuilds - how do YOU do it?

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15 August 2006 - 6:10am
Submitted by: aevans

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 Honk Kong Skyline

So, I am writing this from Hong Kong at almost the end of an 8 day trip out here.  At least, I think it's 8 days.  It could be 10 or 6, I really can't work it out with the time differences and the date line getting involved.  All I know is that when I call home, it's still yesterday.

One of the issues that I am facing at this customer is the need for a top down rebuild of GroupWise.  Now, it's not too often that we really have to do one, but this is one such case.  The challenge is that this customer has 150 global sites and many of them are on the other side of slow WAN links, for example, the other day we needed to rebuild a domain in Johannesburg and the file copy to get the domain there took 6 hours.  6 hours in which admin changes are made, making the domain we just rebuilt out of date (or it would have been if we didn't first suspend the admin thread).

So, what I was wondering was how you guys do it?  I have wondered about getting someone at the local office to download the domain from home and taking it in to the office, or using a file splitter to download multiple chunks, or bittorrent. 

Anyone got any experience with this?




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Alex's picture

I would use rsync. That

Submitted by Alex (not verified) on 19 August 2006 - 6:24pm.

I would use rsync. That way, you can do the intial data copy, and after that, any changes made in the meantime are just a quick update, not an entire copy again.

It saved my bacon just the other day when I had to get data off of a server that wouldn't open eDir due to a "sorta-corrupt" SYS volume. Since rysnc doesn't rely on any sort of eDir authentication, I was able to copy the data off to another server running the rsync daemon without a hitch.

http://forge.novell.com/modules/xfmod/project/?rsync

(Over a slow WAN link, it might be prudent to use the '-z' parameter on the client side to compress the data and preserve bandwidth. Don't bother with it on a LAN, as it is actually slower due to the extra calculation needed.)

Tim O'Keeffe's picture

Sorry I saw this a couple of

Submitted by Tim O'Keeffe (not verified) on 22 August 2006 - 1:42pm.

Sorry I saw this a couple of days late.
It must be either an extremely long time between top downs or there is a bad problem with addresses that the rest of the checks and fixes on the domains couldn't catch.

What I have done on a top down is to First, turn off the Admin piece of the Master Domain.

Then back up the existing WPdomain.db

Then perform your rebuild with the rebuilt file on your local workstation hard drive.

Then take the Master MTA offline and rename the WPdomain.db to something.old or your favorite backup name.

Copy New rebuilt file from your local workstation back to the Master Domain server.

Bring up the Master Domain.
Make sure the Admin piece is running and synced.

Then it is repeat each step for each separate domain.

Just go from one to the next focusing first on the secondary domain.
Key is to turn off the Admin piece only on the domain being worked on.

Timeframe wise it will only be as long as it takes to do a rebuild and manually copying the files over the Wan.

You can rebuild the Post Offices anytime you want after that in whatever order you need as long as their domain file has been rebuilt.

Alex Evans's picture

RSync is an interesting

Submitted by Alex Evans (not verified) on 22 August 2006 - 2:10pm.

RSync is an interesting thought - I actually didn't think of it. Do you have any performance statistics? ie, how long does it take to copy a 100Mb database over a 128Kb link?
I am not sure it would save me huge amounts of time on a one off domain copy though.

Alex Evans's picture

The real issue faced is the

Submitted by Alex Evans (not verified) on 22 August 2006 - 2:20pm.

The real issue faced is the copy across the WAN and how to do that in as short a time as possible. As this customer has so many remote domains on the other side of slow WAN links (64Kb, 128Kb and 256Kb) this is proving to be a real challenge. Their domain db is around 60Mb, so it takes a while to copy.
I'm still kind of pondering this one - I am not sure that any of my ideas would work.
A file splitting download technology (a la GetRight) relies on your pipe being bigger than the download sources pipe, so you have extra bandwidth to do another download
Bittorrents rely on multiple sources, or seeds - neither of these is going to be true.

Aah well!

wes's picture

Let me first say I know

Submitted by wes (not verified) on 22 August 2006 - 4:17pm.

Let me first say I know nothing about the process you are attempting. Is it possible to rebuild the domain on a workstation at the remote site. Maybe zenworks or vnc could be used to get access to a remote computer for the processing. If this is an option you wouldn't need to copy the domains across the WAN

Alex Evans's picture

Unfortunately not - the

Submitted by Alex Evans (not verified) on 22 August 2006 - 7:37pm.

Unfortunately not - the domains get rebuilt from information held in the primary domain, so the rebuilds must happen locally to it. Nice try though :)

Alex's picture

Sorry, no. All we have is

Submitted by Alex (not verified) on 24 August 2006 - 5:39pm.

Sorry, no. All we have is 100mb fiber links :)

I think the biggest advantage in your case is that if the file copy bombs or anything, it will only send the differences once you start it again, as opposed to starting all over.

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