Can I use mkdvd to create bootable DVD from mksysb on tape

UNIX AIX
1

Hi,

Is it possible to use mkdvd to create a bootable DVD using a mksysb on tape as the source image?

On the system concerned, we don't have enough free space to create the mksysb to file first, so would like to use the existing tape mksysb backup.

The DVD disk/s will then be used to boot a different system which doesn't have access to a tape drive.

The man page for mkdvd only says:
-m mksysbimage "Specifies a previously created mksysb image."

TIA.

2

Yes, but it's messy and requires you to copy the file to disk first. Oh.

In theory you could position the tape by skipping forward 2 tape files (or is it 3?) and then using the drive as the parameter for the -m flag, but in practice I would expect this to fail. Give it a try though. You still need space to process it though (see below)

Is there a physical limitation on adding a disk? They are relatively cheap now.

Can you share the output from lsvg , lsvg -l rootvg ? We might be able to work something. Also, the contents of /etc/exclude.rootvg and /image.data

The mkdvd eventually calls readcd with the -w flag (for write) which is rather bizarre, but it need enough space to have two copies of the image whilst it does it. The first is to extract the image in to, then the next is to rebuild making a bootable image to write as a single IO to the media.

Do you have another AIX server with a DVD-RAM drive that does have space?

I sadly no longer have access to AIX servers, but I will see what I can remember.

Kind regards,
Robin

3

Are you sure the tape will deliver the required data rate?

4

Thanks Robin,

The rootvg on this system is around 40GB. Customer keeps a lot of data filesystems in rootvg (we didn't set this up), and doesn't want to change anything. They don't want to add any disk, as the server is migrating off onto our hardware.

In fact I think it's going to be possible for us to make a tape drive available to the destination server, so may not have to worry about the DVDs.

Didn't really want to exclude filesystems from the backup and have to get them across later, hence the question about making the DVDs from the bootable tape backup. Would have been handy if AIX provided that as an option, if not the prettiest solution. From what you say, it sounds like it's not likely to work though, and given that Dr Google doesn't come up with any hits regarding this approach, I'm guessing it's not possible.

Thanks for taking the time to reply though, it's nice to at least know it isn't an option.

Cheers,

5

Okay, a few options.

  • Have a think about using /etc/exclude.rootvg to exclude things in the rootvg not critical to the OS. The way mksysb works, it builds a list of files and funnels them into backbyname (I hope that's right) but using the -e flag on mksysb allows you to pattern-match exclude files which match, so if you have /data, you can write a line in /etc/exclude.rootvg for ./data and it's content will not be written into the image. Hopefully this will fit on disk much easier.
    .
  • Can you NFS mount some space on another server that also has a DVD-RAM device? If so, you could use that to write a DVD based on a mksysb image written across the NFS.

Could you answer the questions above so we know what we're starting with? We've all inherited odd systems so hopefully there is nothing too shocking, even if it's only one volume group.

Thanks, in advance,
Robin