The SLES system will be very easy, the CentOS one a little bit more work because of the way Red Hat uses file system labels and puts those in /etc/fstab.
For the sake of illustration, let's assume that your device numbers and names for the SLES system are: 0300 /dev/dasda1 mounted on / 0301 /dev/dasdb1 mounted on /usr 0610 /dev/dasdc1 (new /) 0611 /dev/dasdd1 (new /usr) If your partitioning and mounting scheme is more complex, this method saves you even more time and trouble. Just expand the instructions to cover all the partitions/file systems you might have. Do an internal Linux disk to disk copy of the two disks: dd if=/dev/dasda of=/dev/dasdc bs=4M dd if=/dev/dasdb of=/dev/dasdd bs=4M You can make the blocksize larger or smaller. Note that I used the whole device nodename, not the partitions, i.e. dasda versus dasda1. This makes sure the IPL text, partition tables, etc. get copied. Before the next step, you may need to run fdasd on the two new volumes, just to make sure the newly-created partition table gets read: fdasd /dev/dasdc1 w fdasd /dev/dasdd1 w Once the two copies are done, mount them on /mnt, as they would be on the new storage array. mount /dev/dasdc1 /mnt mount /dev/dasdd1 /mnt/usr chroot /mnt This will cd to /mnt, then change the environment so that it now appears to be the root directory, hence the name "change root." What you want to do now is edit /etc/zipl.conf so that only the two new volumes are in your dasd list. Save the changes, then re-run zipl. Make sure the messages that come out look right. Then, re-run mkinitrd. Once the new initrd has been created, I would check to make sure that the DASD parameters that get imbedded in it are right: zcat /boot/new.initrd.name > /tmp/initrd.nogz mount -o loop /tmp/initrd.nogz /mnt cd /mnt Look at the linuxrc file to see what it's doing. I don't recall if the initrd has a modules.conf/modprobe.conf in /etc (/mnt/etc at the moment) or not. If it does, look in there. If everything looks fine, cd out of /mnt, umount /mnt, and rm /tmp/initrd.nogz. You should be ready for your changeover to the new storage unit. If you IPL and things go horribly wrong, IPL off the old device and try to fix what was wrong. Note that if you have users or anyone else making changes after the initial copy, you'll need to make those same changes to the new volumes. Now, for the CentOS system, the same methodology will be used, except for the file system labels. Once the two disks have been copied, you'll need to change the file system labels on the new disks. Otherwise, when you try to boot either the old system or the new one, you'll get complaints about duplicate labels, and experience a whole lot of pain (trust me on that one). So, for each file system you have on your original disk, do: e2label /dev/dasda1 e2label /dev/dasdb1 Note the label names. Say they are "/" and "/usr" respectively. Then change them on the new file systems: e2label /dev/dasdc1 /new e2label /dev/dadsd1 /usrnew Once you mount /dev/dasdc1 and /dev/dasdd1 on /mnt and /mnt/usr, edit /mnt/etc/fstab, and change the entries: LABEL=/ LABEL=/usr To LABEL=/new LABEL/usrnew That should be the only difference between the two OSes. I just sat down and wrote this up, so I haven't had a chance to test its correctness. So, before you try this, read it over and ask questions about anything that doesn't make sense to you. Mark Post -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Henderson.Louis Sent: Thursday, May 18, 2006 5:41 PM To: [email protected] Subject: Re: Moving from ESS 800 to DS8100 Yes, I have physical access now. But "permission" starting next weekend 5/27. Concurrent access for about two weeks. What is the nit? Louis E. Henderson SharedServices - Mainframe - x5392 -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Post, Mark K Sent: Thursday, May 18, 2006 2:02 PM To: [email protected] Subject: Re: Moving from ESS 800 to DS8100 Will you have concurrent access to both sets of disk at some point? That will make the migration almost a nit. Mark Post -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Henderson.Louis Sent: Thursday, May 18, 2006 4:30 PM To: [email protected] Subject: Moving from ESS 800 to DS8100 I have two zLINUX LPARS. One is SLESS 9 and the other is CentOS 4. We are migrating from an ESS 800 to DS8100. All unit addresses for DASD will change. Network address will not. Is there any documentation on how to migrate to the new devices? Each zLINUX system has two 3390 Mod 9 volumes. Any experiences, pointers or documentation would be appreciated. Louis E. Henderson SharedServices - Mainframe ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
