Migrating to AIX 6.1 with
nimadm
Reference: http://www.ibm.com/
Preparation
There are a few
requirements that must be met before attempting to use nimadm to migrate
to AIX 6.1. I'll mention just some of these here. I recommend that you review
the online documentation for nimadm or the IBM NIM Redbook for more
information (see the Resources section at the end of this article).- You must have a NIM master running AIX 6.1 or higher with the latest
Technology Level or higher.
- The NIM master must have the bos.alt_disk_install.rte
fileset installed in its own rootvg and in the SPOT that will be used for the migration. Both need to be at the same
level. It is not necessary to install the alternate disk utilities
on the client.
- The lpp_source and SPOT NIM resources
that have been selected for the migration MUST match the AIX level to
which you are migrating.
- The NIM master (as always) should be
at the same or higher AIX level than the level you are migrating to on the
client.
- The target client must be registered
with the NIM master as a standalone NIM client.
- The NIM master must be able to
execute remote commands on the client using rsh.
- Ensure the NIM client has a spare
disk (not allocated to a volume group) large enough to contain a complete
copy of its rootvg. If rootvg is
mirrored, break the mirror and use one of the disks for the migration.
- Ensure the clients NIM master has a
volume group (for example, nimadmvg) with enough free space to cater for a
complete copy of the client's rootvg. If more than one AIX migration is
occurring for multiple NIM clients, make sure there is capacity for a copy
of each clients rootvg.
By default, the nimadm tool utilizes NFS for many of the tasks during the migration. This can be a problem on slower networks because NFS writes can be very expensive. To avoid using NFS, a Local Disk Caching option exists that can provide some performance advantages.
Local disk
caching allows the NIM master to avoid having to use NFS to write to the
client. This can be useful if the nimadm operation is not performing
well due to an NFS write bottleneck.
If the Local Disk
Caching function is invoked, then nimadm will create the client file
systems in a volume group on the NIM master. It will then use streams (via
rshd) to cache all of the data from the client to the file systems on the NIM
master.
The advantages of local disk caching over NFS
could be summarized as:
Improved performance for nimadm
operations on relatively slow networks. - Improved performance for nimadm
operations that are bottlenecked in NFS writes.
- Decreased CPU usage on the client.
- Client file systems not exported.
- Allows TCB enabled systems to be
migrated with nimadm.
- Cache file systems take up space on
the NIM master. You must have enough disk space in a volume group on the
NIM master to host the client's rootvg file systems, plus some space for
the migration of each client.
- Increased CPU usage on the NIM
master.
- Increased I/O on the master. For best
performance, use a volume group on the NIM master that does not contain
the NIM resources being used for the AIX migration.
For performance
reasons, we deploy Local Disk Caching with nimadm in our environment.
The nimadm
command performs a migration in 12 phases. It is useful to have some knowledge
of each phase before performing a migration. - The master issues the alt_disk_install command to the
client, which makes a copy of the clients
rootvg to the target disks. In this phase, the alternate root volume
group (altinst_rootvg) is
created.
- The NIM master creates the cache file
systems in the nimadmvg volume
group. Some initial checks for the required migration disk space are
performed.
- The NIM master copies the NIM client's
data to the cache file systems in nimadmvg.
This data copy is done via rsh.
- If a pre-migration script resource
has been specified, it is executed at this time.
- System configuration files are saved.
Initial migration space is calculated and appropriate file system
expansions are made. The bos image is restored and the device database is
merged (similar to a conventional migration). All of the migration merge
methods are executed, and some miscellaneous processing takes place.
- All system filesets are migrated
using installp. Any required RPM images are also installed during this
phase.
- If a post-migration script resource
has been specified, it is executed at this time.
- The bosboot command is run to create
a client boot image, which is written to the client's alternate boot
logical volume (alt_hd5).
- All the migrated data is now copied
from the NIM master's local cache file and synced to the client's
alternate rootvg via rsh.
- The NIM master cleans up and removes
the local cache file systems.
- The alt_disk_install command is
called again to make the final adjustments and put altinst_rootvg to sleep. The bootlist is set to the target disk.
- Cleanup is executed to end the
migration.
If you are unable to meet the requirements for phases 1 to
10, then you should consider performing a conventional migration.
Before we move
onto a nimadm example, I just want to add a few points for you to
consider first.- I recommended that you do not to make
any changes to your system once the migration is underway, such as adding
users, changing passwords, adding print queues, and the like. If possible,
wait until the migration has finished and the system has been rebooted on
the new version of AIX. If you must perform administration tasks prior to
the reboot, you should take note of the changes and re-apply them to the
system after it has been rebooted into AIX 6.1.
- We developed, tested, and verified
our migration procedures several times before implementing them on our
production systems. This allowed us time to verify that the steps were
correct and that the AIX migrations would complete as expected. I
recommend you do the same.
·
If
you have a multibos image in rootvg, remove it. AIX migrations are not supported with multibos enabled
systems. Ensure all
rootvg LVs are renamed to their legacy names. If necessary, create a new
instance of rootvg and reboot the LPAR. For example:
# multibos –sXp
# multibos –sX
# shutdown –Fr
|
# lsvg -l rootvg |
grep hd | grep open
hd6 paging 80
160 2 open/syncd N/A
hd8 jfs2log 1
2 2 open/syncd N/A
hd4 jfs2 1
2 2
open/syncd /
hd2 jfs2 7
14 2 open/syncd /usr
hd3 jfs2 16
32 2 open/syncd /tmp
hd1 jfs2 1
2 2 open/syncd /home
hd9var jfs2 8
16 2
open/syncd /var
hd7 sysdump 8
8 1 open/syncd N/A
hd7a sysdump 8
8 1 open/syncd N/A
hd10opt jfs2 8
16 2 open/syncd /opt
|
Remove the old multibos instance.
|
# multibos -R
|
Migrating to AIX 6.1 using nimadm
Let's use nimadm
now to migrate an AIX system. Ensure that you document the system and perform a
mksysb before performing any maintenance activity. You know this already,
right? But I have to say it!
We will migrate a
system from AIX 5.3 to AIX 6.1. The NIM master in this environment is running AIX 6.1 TL3 SP2. Our NIM client name is
aix1 (running AIX 5.3 TL7 SP5 and migrating to AIX 6.1 TL3 SP1) and the NIM masters name is nim1.
Little
make more easier:
|
Nimserver
|
Client
|
|
Nimserver
Name ---------- > nim1
|
Client
Name --- > aix1
|
|
Nimserver
level ------------ > AIX 6.1 TL3 SP2
|
Client
Oslevel (who is going to migrate) -- >
AIX 5.3 TL7 SP5
|
Prior to a
migration, it is always a good idea to run the pre_migration script on the system to catch any issues that may
prevent the migration from completing successfully. You can find this script on
the AIX 6.1 installation media.
Run this script,
review the output (in /home/pre_migration), and correct any issues that it
reports before migrating.|
#./pre_migration
All saved information can be found in:
/home/pre_migration.090903105452
Checking size of boot logical volume (hd5).
Your rootvg has mirrored logical volumes (copies
greater than 1)
Recommendation:
Break existing mirrors before migrating.
Listing software that will be removed from the
system.
Listing configuration files that will not be
merged.
Listing configuration files that will be merged.
Saving configuration files that will be merged.
Running lppchk commands. This may take awhile.
Please check
/home/pre_migration.090903105452/software_file_existence_check
for possible errors.
Please check
/home/pre_migration.090903105452/software_checksum_verification
for possible errors.
Please check /home/pre_migration.090903105452/tcbck.output
for possible errors.
All saved information can be found in:
/home/pre_migration.090903105452
It is recommended that you create a bootable
system backup of your system
before migrating.
|
If rootvg is
mirrored, I break the mirror and reduce it to a single disk. This gives me a
spare disk that can be used for the migration.
To allow nimadm
to do its job, I must temporarily enable rshd on the client LPAR. I will
disable it again after the migration.|
# chsubserver -a -v shell -p tcp6 -r inetd
# refresh –s inetd
# cd /
# rm .rhosts
# vi .rhosts
+
# chmod 600 .rhosts
|
On the NIM
master, I can now 'rsh' to the client and run a command as root.
|
# rsh aix1 whoami
root
|
On the NIM
master, I have created a new volume group (VG) named nimadmvg. This VG has
enough capacity to cater for a full copy of the NIM clients root volume group
(rootvg). This VG will be empty until the migration is started.
Likewise, on the
NIM client, I have a spare disk which has enough capacity for a full copy of
its rootvg.
On the master (nim1):
|
# lsvg -l nimadmvg
nimadmvg:
LV NAME
TYPE LPs PPs
PVs LV STATE MOUNT POINT
|
|
# lspv
hdisk0 0000273ac30fdcfc
rootvg active
hdisk1 000273ac30fdd6e
None
|
The fileset bos.alt_disk_install.rte fileset is
installed on the NIM master:
|
# lslpp -l bos.alt_disk_install.rte
Fileset
Level State Description
----------------------------------------------------------------------------
Path: /usr/lib/objrepos
bos.alt_disk_install.rte
6.1.3.1 APPLIED Alternate Disk Installation
Runtime
|
|
# nim -o showres 'spotaix61031' | grep bos.alt_disk_install.rte
bos.alt_disk_install.rte
6.1.3.1 C F
Alternate Disk Installation
|
OR
|
# nim -o lslpp -a
filesets="bos.alt_disk_install.rte" spotaix61031
Fileset Level State
Description
----------------------------------------------------------------------------
Path: /usr/lib/objrepos
bos.alt_disk_install.rte
6.1.3.1 COMMITTED Alternate Disk Installation
Runtime
#
|
# smitty nim
Perform NIM Administration Tasks
Manage Resources
Perform operations on Resources
<< choose your spot >>
|
Customize a SPOT
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
* Resource Name spotaix61031
* Source of Install Images [lpp_61] +
Fileset Names
[bos.alt_disk_install.rte]
installp Bundle [] +
Fixes (Keywords) []
Fix Bundle (Keyword Bundle) [] +
Expand file systems if space
needed? yes +
Force
no +
installp Flags
PREVIEW only? (install operation
will NOT occur) no +
COMMIT software updates? no +
SAVE replaced files? yes +
AUTOMATICALLY install requisite
software? yes +
OVERWRITE same or newer
versions? no +
VERIFY install and check file
sizes? no +
ACCEPT new license agreements? yes
+
(AIX V5 and higher machines
and resources)
Preview new LICENSE
agreements? no
|
|
# nimadm -j nimadmvg -c aix1 -s spotaix61031
-l lppsourceaix61031 -d "hdisk1" –Y
|
Where:
- –j flag specifies the VG on the
master which will be used for the migration
- -c is the client name
- –s is the SPOT name
- -l is the lpp_source name
- -d is the hdisk name for the
alternate root volume group (altinst_rootvg)
- –Y agrees to the software license
agreements for software that will be installed during the migration.
Now I can sit
back and watch the migration take place. All migration activity is logged on
the NIM master in the /var/adm/ras/alt_mig directory. For this migration, the
log file name is aix1_alt_mig.log. Here's a sample of some of the output you
can expect to see for each phase:
|
MASTER DATE:
Mon Nov 9 14:29:09 EETDT 2009
CLIENT DATE:
Mon Nov 9 14:29:09 EETDT 2009
NIMADM
PARAMETERS: -j nimadmvg -c aix1 -s spotaix61031 -l lppsourceaix61031 -d
hdisk1 -Y
Starting
Alternate Disk Migration.
+----------------------------------------------------------------------+
Executing nimadm phase 1.
+----------------------------------------------------------------------+
Cloning
altinst_rootvg on client, Phase 1.
Client
alt_disk_install command: alt_disk_copy -j -i /ALT_MIG_IMD -M 6.1 -P1 -d
"hdisk1"
Checking disk
sizes.
Creating cloned
rootvg volume group and associated logical volumes.
Creating
logical volume alt_hd5.
Creating
logical volume alt_hd6.
Creating
logical volume alt_hd8.
Creating
logical volume alt_hd4.
Creating
logical volume alt_hd2.
Creating
logical volume alt_hd9var.
Creating
logical volume alt_hd3.
Creating
logical volume alt_hd1.
Creating
logical volume alt_hd10opt.
Creating
logical volume alt_hd7.
Creating
logical volume alt_local_lv.
Creating
logical volume alt_varloglv.
Creating
logical volume alt_nmonlv.
Creating
logical volume alt_chksyslv.
Creating
logical volume alt_hd71.
Creating
logical volume alt_auditlv.
Creating
logical volume alt_nsrlv.
Creating
logical volume alt_hd11admin.
Creating
/alt_inst/ file system.
Creating
/alt_inst/admin file system.
Creating
/alt_inst/home file system.
Creating
/alt_inst/home/nmon file system.
Creating
/alt_inst/nsr file system.
Creating
/alt_inst/opt file system.
Creating
/alt_inst/tmp file system.
Creating
/alt_inst/usr file system.
Creating
/alt_inst/usr/local file system.
Creating
/alt_inst/usr/local/chksys file system.
Creating
/alt_inst/var file system.
Creating
/alt_inst/var/log file system.
Creating
/alt_inst/var/log/audit file system.
Generating a
list of files
for backup and
restore into the alternate file system...
Phase 1
complete.
+----------------------------------------------------------------------+
Executing
nimadm phase 2.
+----------------------------------------------------------------------+
Creating nimadm
cache file systems on volume group nimadmvg.
Checking for
initial required migration space.
Creating cache
file system /aix1_alt/alt_inst
Creating cache
file system /aix1_alt/alt_inst/admin
Creating cache
file system /aix1_alt/alt_inst/home
Creating cache
file system /aix1_alt/alt_inst/home/nmon
Creating cache
file system /aix1_alt/alt_inst/nsr
Creating cache
file system /aix1_alt/alt_inst/opt
Creating cache
file system /aix1_alt/alt_inst/tmp
Creating cache
file system /aix1_alt/alt_inst/usr
Creating cache
file system /aix1_alt/alt_inst/usr/local
Creating cache
file system /aix1_alt/alt_inst/usr/local/chksys
Creating cache
file system /aix1_alt/alt_inst/var
Creating cache
file system /aix1_alt/alt_inst/var/log
Creating cache
file system /aix1_alt/alt_inst/var/log/audit
+----------------------------------------------------------------------+
Executing
nimadm phase 3.
+----------------------------------------------------------------------+
Syncing client
data to cache ...
+----------------------------------------------------------------------+
Executing
nimadm phase 4.
+----------------------------------------------------------------------+
nimadm: There
is no user customization script specified for this phase.
+----------------------------------------------------------------------+
Executing nimadm
phase 5.
+----------------------------------------------------------------------+
Saving system
configuration files.
Checking for
initial required migration space.
Setting up for
base operating system restore.
/aix1_alt/alt_inst
Restoring base
operating system.
Merging system
configuration files.
Running
migration merge method: ODM_merge Config_Rules.
Running
migration merge method: ODM_merge SRCextmeth.
Running
migration merge method: ODM_merge SRCsubsys.
Running
migration merge method: ODM_merge SWservAt.
Running
migration merge method: ODM_merge pse.conf.
Running
migration merge method: ODM_merge vfs.
Running
migration merge method: ODM_merge xtiso.conf.
Running
migration merge method: ODM_merge PdAtXtd.
Running
migration merge method: ODM_merge PdDv.
Running
migration merge method: convert_errnotify.
Running
migration merge method: passwd_mig.
Running
migration merge method: login_mig.
Running
migration merge method: user_mrg.
Running
migration merge method: secur_mig.
Running
migration merge method: RoleMerge.
Running
migration merge method: methods_mig.
Running
migration merge method: mkusr_mig.
Running
migration merge method: group_mig.
Running
migration merge method: ldapcfg_mig.
Running
migration merge method: ldapmap_mig.
Running
migration merge method: convert_errlog.
Running
migration merge method: ODM_merge GAI.
Running
migration merge method: ODM_merge PdAt.
Running
migration merge method: merge_smit_db.
Running
migration merge method: ODM_merge fix.
Running
migration merge method: merge_swvpds.
Running
migration merge method: SysckMerge.
+----------------------------------------------------------------------+
Executing
nimadm phase 6.
+----------------------------------------------------------------------+
Installing and
migrating software.
Updating
install utilities.
+----------------------------------------------------------------------+
Pre-installation Verification...
+----------------------------------------------------------------------+
Verifying
selections...done
Verifying requisites...done
Results...
|
…output
truncated….
|
install_all_updates:
Generating list of updatable rpm packages.
install_all_updates:
No updatable rpm packages found.
install_all_updates:
Checking for recommended maintenance level 6100-03.
install_all_updates:
Executing /usr/bin/oslevel -rf, Result = 6100-03
install_all_updates:
Verification completed.
install_all_updates:
Log file is /var/adm/ras/install_all_updates.log
install_all_updates:
Result = SUCCESS
Restoring
device ODM database.
+----------------------------------------------------------------------+
Executing
nimadm phase 7.
+----------------------------------------------------------------------+
nimadm: There
is no user customization script specified for this phase.
+----------------------------------------------------------------------+
Executing
nimadm phase 8.
+----------------------------------------------------------------------+
Creating client
boot image.
bosboot: Boot
image is 40952 512 byte blocks.
Writing boot
image to client's alternate boot disk hdisk1.
+----------------------------------------------------------------------+
Executing
nimadm phase 9.
+----------------------------------------------------------------------+
Adjusting
client file system sizes ...
Adjusting size
for /
Adjusting size
for /admin
Adjusting size
for /home
Adjusting size
for /home/nmon
Adjusting size
for /nsr
Adjusting size
for /opt
Adjusting size
for /tmp
Adjusting size
for /usr
Adjusting size
for /usr/local
Adjusting size
for /usr/local/chksys
Adjusting size
for /var
Adjusting size
for /var/log
Adjusting size
for /var/log/audit
Syncing cache
data to client ...
+----------------------------------------------------------------------+
Executing
nimadm phase 10.
+----------------------------------------------------------------------+
Unmounting
client mounts on the NIM master.
forced unmount
of /aix1_alt/alt_inst/var/log/audit
forced unmount
of /aix1_alt/alt_inst/var/log
forced unmount
of /aix1_alt/alt_inst/var
forced unmount
of /aix1_alt/alt_inst/usr/local/chksys
forced unmount
of /aix1_alt/alt_inst/usr/local
forced unmount
of /aix1_alt/alt_inst/usr
forced unmount
of /aix1_alt/alt_inst/tmp
forced unmount
of /aix1_alt/alt_inst/opt
forced unmount
of /aix1_alt/alt_inst/nsr
forced unmount
of /aix1_alt/alt_inst/home/nmon
forced unmount
of /aix1_alt/alt_inst/home
forced unmount
of /aix1_alt/alt_inst/admin
forced unmount
of /aix1_alt/alt_inst
Removing nimadm
cache file systems.
Removing cache
file system /aix1_alt/alt_inst
Removing cache
file system /aix1_alt/alt_inst/admin
Removing cache
file system /aix1_alt/alt_inst/home
Removing cache
file system /aix1_alt/alt_inst/home/nmon
Removing cache
file system /aix1_alt/alt_inst/nsr
Removing cache
file system /aix1_alt/alt_inst/opt
Removing cache
file system /aix1_alt/alt_inst/tmp
Removing cache
file system /aix1_alt/alt_inst/usr
Removing cache
file system /aix1_alt/alt_inst/usr/local
Removing cache
file system /aix1_alt/alt_inst/usr/local/chksys
Removing cache
file system /aix1_alt/alt_inst/var
Removing cache
file system /aix1_alt/alt_inst/var/log
Removing cache
file system /aix1_alt/alt_inst/var/log/audit
+----------------------------------------------------------------------+
Executing
nimadm phase 11.
+----------------------------------------------------------------------+
Cloning
altinst_rootvg on client, Phase 3.
Client
alt_disk_install command: alt_disk_copy -j -i /ALT_MIG_IMD -M 6.1 -P3 -d
"hdisk1"
## Phase 3
###################
Verifying
altinst_rootvg...
Modifying ODM
on cloned disk.
forced unmount
of /alt_inst/var/log/audit
forced unmount
of /alt_inst/var/log
forced unmount
of /alt_inst/var
forced unmount
of /alt_inst/usr/local/chksys
forced unmount
of /alt_inst/usr/local
forced unmount
of /alt_inst/usr
forced unmount
of /alt_inst/tmp
forced unmount
of /alt_inst/opt
forced unmount
of /alt_inst/nsr
forced unmount
of /alt_inst/home/nmon
forced unmount
of /alt_inst/home
forced unmount
of /alt_inst/admin
forced unmount
of /alt_inst
Changing
logical volume names in volume group descriptor area.
Fixing LV
control blocks...
Fixing file
system superblocks...
Bootlist is set
to the boot disk: hdisk1 blv=hd5
+----------------------------------------------------------------------+
Executing
nimadm phase 12.
+----------------------------------------------------------------------+
Cleaning up
alt_disk_migration on the NIM master.
Cleaning up
alt_disk_migration on client aix1.
|
After the
migration is complete, I confirm that the bootlist is set to the nst_rootvg
disk.
|
# lspv | grep
rootvg
hdisk0
0000273ac30fdcfc rootvg active
hdisk1 000273ac30fdd6e altinst_rootvg active
# bootlist -m
normal -o
hdisk1 blv=hd5
#
|
At an agreed
time, I reboot the LPAR and confirm that the system is now running AIX 6.1.
|
# shutdown –Fr
; system
reboots here…
# oslevel –s
6100-03-01-0921
# instfix -i |
grep AIX
All filesets for 6.1.0.0_AIX_ML were
found.
All filesets for 6100-00_AIX_ML were
found.
All filesets for 6100-01_AIX_ML were
found.
All filesets for 6100-02_AIX_ML were
found.
All filesets for 6100-03_AIX_ML were
found.
|
At this point, I
would perform some general AIX system health checks to ensure that the system is configured
and running as I'd expect. There is also a post_migration script that you can
run to verify the migration. You can find this script in /usr/lpp/bos, after
the migration.
You may want to
consider upgrading other software such as openssl, openssh, lsof, etc at this
stage.
The rsh daemon
can now be disabled after the migration.
|
# chsubserver
-d -v shell -p tcp6 -r inetd
# refresh –s
inetd
# cd /
# rm .rhosts
# ln -s
/dev/null .rhosts
|
With the
migration finished, the applications are started and the application support
team verify that everything is functioning as expected. I also take a mksysb
and document the system configuration after the migration.
Once we are all
satisfied that the migration has completed successfully, we then return rootvg
to a mirrored disk configuration.
|
# lspv | grep old_rootvg
hdisk0 000071da26fe3bd0 old_rootvg
#
# alt_rootvg_op -X old_rootvg
# extendvg –f rootvg hdisk0
# mirrorvg rootvg hdisk0
# bosboot -a -d /dev/hdisk0
# bosboot -a -d /dev/hdisk1
# bootlist -m normal hdisk0 hdisk1
# bootlist -m normal -o
hdisk0 blv=hd5
hdisk1 blv=hd5
#
|
If there was an
issue with the migration, I could easily back out to the previous release of
AIX. Instead of re-mirroring rootvg (above), we would change the boot list to
point at the previous rootvg disk (old_rootvg) and reboot the LPAR.
|
# lspv | grep old_rootvg
hdisk0 000071da26fe3bd0 old_rootvg
# bootlist -m normal hdisk0
# bootlist -m normal –o
hdisk0 blv=hd5
# shutdown –Fr
|
This is much
simpler and faster than restoring a mksysb image (via NIM, tape, or DVD), as
you would with a conventional migration method.