rsync vs MirrorDisk

[Kim Kendall]

Has anyone else been faced with having to figure out how to kobble a 'home-grown' MirrorDisk substitute together?

Was thinking of using dd from one device to the other. (nah)

Disk 1 is a boot disk, so I think I could only use rsync for the data files only, and only to a seperate mount point for that second device. So in essence, it merely becomes an online backup (or a "snapshot") of the data.

I also believe I wouldn't be able to make the second drive bootable since I have to do a "lvextend -m 1" command in the process of making it.

pvcreate
vgextend
mkboot -l
mkboot -a
lvextend <- This is where it falls apart?
---------------------------------------------
I suppose I could try a make_net_recovery (no tape drive either) of drive one, do a vgexport and save the file, then swap drive one with the other and restore to it. Then vgimport the original drive (as vg01) and mount just the data partition from it...Then rsync might be a workable solution.

I'm beginning to feel like the activities director at camp patch-em-up.

[Xavier Gutierrez_1]

Hi, Kim.

I understand that you want to maintain some kind of mirror between to system disks without having to buy MirrorDisk-UX.

That's a hard work. Let's consider a few options:


1.- Your disks are NOT Hot-Pluggable.

The option you have is to create another VG, p.e. VG01, with a single lvol and to add a mount point for it.

Then, you can copy all the data from your VG00 to this disk by doing something like:

find
/var
/usr
/opt
.
.
.
/stand

-depth -print | cpio -pd

The bad point is that, if your boot disk fails, you have to install the base OS onto the new disk, boot from it and then import the VG01.

Once this is done, you'll need to execute the following:

cd
find . -depth -print | cpio -pd /


2.- Your disks are Hot-Pluggable.

In this case, you just need to do a dd:

dd if=/dev/rdsk/"bootdisk" of=/dev/rdsk/"newdisk" bs=1024k

After the dd is completed, remove the new disk (Hot-Unplug it from your system); otherwise, if your machine reboots you will have real trouble (i.e. the kernel will see the same PVRA on both disks and it will thik it's the alternate path for the boot disk).

In case of a boot disk failure, shut down the machine and remove the boot disk, then plug the new disk (the one that you did the dd to) in it's place. The you only have to power up the system and let it boot normally.


Best regards.

[Clemens van Everdingen]

Hi,

Although the answer before is quiet ok, I would prefer to use Mirror-Disk UX or Ignite.

These are supported solutions, which might enable you to get support in case anything really fails.

C.

[harry d brown jr]

Are you kidding me? You have probably wasted enough time thinking about this to pay for mirror-ux!

live free or die
harry

[Kim Kendall]

I know Harry... But when the chief saw that the license was "per processor", he got pissed. This whole circus will end up costing more in the long run to mickey mouse something together.

I'm adding 3 new systems (rp2470's) soon and was going to get MirrorDisk/UX , and that was fine till he found out I had to buy qty 6 licenses. (dual proc systems)

I'm still leaning toward doing either a dd to the second drive.... or .... my original idea of doing a make_net_recovery, and a vgexport, and then restoring the recovery to the second drive.

And then vgimport the original disk but only mount the data partition from it and leave the OS partitions unmounted. Then if os drive fails, I can boot to the other drive and still be in business.

I'm also looking into older de-comissioned systems that (I'm sure) had MirrorDisk on them. I will perhaps move the MirrorDisk from them to the new systems (I hope).

##############

Anybody have any experience dealing with HP in this area where you had to move a license? Just how painful will this be?