I have recently taken over responsibility for an RS6000 installed 6
years ago, and while I have some AIX admin knowledge, I am not a
trainrf admin. I ended up with this responsibility because I know more
about AIX than any of the other people here. I'm sure many of you know
what that is like.....

The box is an RS6000 - E30 running AIX 4.2.1. It has 4 by 2Gb hard
discs all of which belong to the single volume group, rootvg.

I am having intermittent hard disc problems with Hdisk0 and believe it
should be replaced.

This disk not only contains most of the basic OS file systems, but
also some raw logical volumes used by a Sybase database, so using a
mksysb will not be enough.

What I am looking for is a method / software (commerical or
shareware/freeware) which would allow me to transparently replace
Hdisk0 with another disc without the need for extensive manual mucking
around requiring extensive admin knowledge I do not have. As the
subject line says, I'm looking to do a transparent RAID style swap in
a non-RAID system.

This is the production machine for the company so it will become
urgent in the near future.

Any suggestions / pointers / ideas will be much appreciated! Thanks.

Tom.

On 5/12/03 3:59 pm, in article
5349f6b1.0312050759.dab47b@posting.google.com, "Tom Brehony"
<tomb@lk.blackbird.ie> wrote:

> I have recently taken over responsibility for an RS6000 installed 6
> years ago, and while I have some AIX admin knowledge, I am not a
> trainrf admin. I ended up with this responsibility because I know more
> about AIX than any of the other people here. I'm sure many of you know
> what that is like.....

Your first mistake - or the person who built the box's first mistake was
having application and application data on rootvg. This is generally
considered a major no for the reasons you've just described.

The best way to configure an AIX box is to have two disks in the rootvg, one
mirrored onto the other and only containing the OS and default paging. All
application data can then go on other disks of your choice, whether they be
SCSI, SSA, Fibre, SAN etc

I don't know of any shareware that could do what you want but the only way I
can think of is based on how much space you have on the other disks. If you
have a free disk, you could mirror hdisk0 onto that disk but you'll need a
whole free disk and the OS logical volumes will also need to be on a single
disk i.e. Not spread across two disks. If all disks are used, then you are
screwed! Sorry for being blunt!

I would try to get an export of the Sybase database onto files, back them up
then you'll have to do a reinstall of the OS (you could do a mksysb but the
sybase raw lv's will be missing as a mksysb only backs up mounted
filesystems), then create the new raw lv's and import the export back into
Sybase. I think you'll need to explain to your employers that the system is
heading for a major fall!

tomb@lk.blackbird.ie (Tom Brehony) wrote in message news:<5349f6b1.0312050759.dab47b@posting.google.co m>...
> I have recently taken over responsibility for an RS6000 installed 6
> years ago, and while I have some AIX admin knowledge, I am not a
> trainrf admin. I ended up with this responsibility because I know more
> about AIX than any of the other people here. I'm sure many of you know
> what that is like.....
>
> The box is an RS6000 - E30 running AIX 4.2.1. It has 4 by 2Gb hard
> discs all of which belong to the single volume group, rootvg.
>
> I am having intermittent hard disc problems with Hdisk0 and believe it
> should be replaced.
>
> This disk not only contains most of the basic OS file systems, but
> also some raw logical volumes used by a Sybase database, so using a
> mksysb will not be enough.
>
> What I am looking for is a method / software (commerical or
> shareware/freeware) which would allow me to transparently replace
> Hdisk0 with another disc without the need for extensive manual mucking
> around requiring extensive admin knowledge I do not have. As the
> subject line says, I'm looking to do a transparent RAID style swap in
> a non-RAID system.
>
> This is the production machine for the company so it will become
> urgent in the near future.
>
> Any suggestions / pointers / ideas will be much appreciated! Thanks.
>
> Tom.

We might be able to help, but you will need to post the output of lsvg
rootvg, lspv -l hdisk0, lspv -l hdisk1, lspv -l hdisk2, lspv -l
hdisk3 and lspv hdisk0. We can than see if you've got any space free
on any of the disks and move logical volumes off hdisk0 so that you
can have a disk that contains all the LV's required onto one disk.
Unfortunately you are going to HAVE to perform some manual tasks.

Steve

> I have recently taken over responsibility for an RS6000 installed 6
> years ago, and while I have some AIX admin knowledge, I am not a
> trainrf admin. I ended up with this responsibility because I know more
> about AIX than any of the other people here. I'm sure many of you know
> what that is like.....
>
> The box is an RS6000 - E30 running AIX 4.2.1. It has 4 by 2Gb hard
> discs all of which belong to the single volume group, rootvg.
>
> I am having intermittent hard disc problems with Hdisk0 and believe it
> should be replaced.
>
> This disk not only contains most of the basic OS file systems, but
> also some raw logical volumes used by a Sybase database, so using a
> mksysb will not be enough.
>
> What I am looking for is a method / software (commerical or
> shareware/freeware) which would allow me to transparently replace
> Hdisk0 with another disc without the need for extensive manual mucking
> around requiring extensive admin knowledge I do not have. As the
> subject line says, I'm looking to do a transparent RAID style swap in
> a non-RAID system.
>
> This is the production machine for the company so it will become
> urgent in the near future.
>
> Any suggestions / pointers / ideas will be much appreciated! Thanks.
>

What about temporarily connecting a new hdisk to the external SCSI Port.
Then mirror (and sync!!!) all lv's from hdisk0 to the temporary hdisk4.
After all is mirrored call bosboot if the boot lv was on hdisk0.

Then reboot and look if all is working. Next delete all lv copies from
hdisk0, shutdown and replace hdisk0.

Next you can move the lv's from hdisk4 back to hdisk0, don't forget
"bosboot".

All you need is
extendvg, mklvcopy, syncvg, rmlvcopy, reducevg and perhaps bosboot

The longer running tasks can be done while machine is online.
Don't know if the hdisks in a E30 are hot-swappable.


If you have a replacement hdisk of identical size or up to 10% larger
you can boot your AIX cd and make a copy of pv as long as all data on
hdisk0 is accessable and consistent. The task is easier, but will cause
a few hours offline instead only a few minutes.

A disk layout with database raw devices in rootvg isn't appropiate for a
long running production machine. It's ok for a quick'n'dirty development
machine when you need to spread the I/O on a small machine as much as
possible.

AIX's volume manager is your friend.

---
Uli