Re: Re-mirroring rootvg

Obi-Wan wrote:
We recently upgraded a machine to AIX 5.3 by breaking the mirrored
rootvg & upgrading only one of the disks. That went fine, but now
that we're sure all is well, we need to re-mirror rootvg again. Alas,
I'm having trouble finding two documentation sources that agree with
each other on exactly how we're supposed to do this.

The active (5.3) disk is hdisk0, and the inactive (4.3.2) disk is hdisk1.
I'm pretty sure that, at a minimum, I need to run:

extendvg rootvg hdisk1
mirrorvg rootvg
you can use: mirrorvg rootvg hdisk1 ( mirrorvg will extend the rootvg )
bootlist -m normal -o hdisk0 hdisk1 cd0
I think to -o option is wrong if setting the bootlist. The correct
syntax should be:
bootlist -m normal -o hdisk0 hdisk1 cd0

I use the following commands if both disk have the same size and the
new disk has no active lvs

mirrorvg -m rootvg hdisk1
# -m creates an exact copy of the rootvg - hd5 should be fine and
# so no need for the lslv -m hd5 check
syncvg -v rootvg
chvg -Qn rootvg
bosboot -ad /dev/hdisk1
bosboot -ad /dev/hdisk0
# I do the bosboot on both disks. Do not ask me why.
bootlist -m normal hdisk0 hdisk1 cd0
# Reboot to activate quorum

Or read the IBM Technote:

From IBM website: Search was: +mirrorvg +technote
http://www-1.ibm.com/support/docview.wss?uid=isg3T1000358

In case the link will fail:

Contents of the technote
....
Mirroring the rootvg Volume Group for AIX Versions 4.3.3 and 5
Technote (FAQ)

Problem
Mirroring the rootvg Volume Group for AIX Versions 4.3.3 and 5

Solution
This document specifies the supported method for mirroring the rootvg
volume group to provide high availability access of the AIX operating
system. There are four steps required in mirroring rootvg:

Mirror rootvg using mirrorvg or mklvcopy.
Make the new mirrored disk bootable by running bosboot.
Add the new mirrored disk to the bootlist.
Reboot the system to disable quorum.
This function is not supported on /usr client, diskless client, or
dataless client systems.

This document is only valid for AIX Versions 4.3.3 and 5.

Why mirror the rootvg volume group?
Procedure
Known problems
--------------------------------------------------------------------------------

Why mirror the rootvg volume group?
Mirroring the rootvg volume group is important because:

Maintaining an active mirrored copy of the rootvg volume on another
disk ensures continuous operation of the AIX operating system in the
event that a disk that is part of the operating system experiences
failure.
Such maintenance provides the ability to boot more than one disk of the
rootvg in the event that another boot disk has failed. In some cases,
the ability to boot from alternate disks may require some user
intervention.

--------------------------------------------------------------------------------

Procedure
To mirror the entire contents of rootvg volume group, use the mirrorvg
command. Assuming rootvg is on hdisk0 and that hdisk1 is the physical
volume to mirror to, use the following syntax:
mirrorvg rootvg hdisk1

You will receive a message similar to:

0516-1124 mirrorvg: Quorum requirement turned off, reboot system
for this
to take effect for rootvg.
0516-1126 mirrorvg: rootvg successfully mirrored, user should
perform
bosboot of system to initialize boot records. Then, user must
modify
bootlist to include: hdisk1 hdisk0.

If user has user-created logical volumes in rootvg and does not want to
mirror those, the mklvcopy command may be used instead to mirror only
the standared rootvg logical volumes, such as hd1, hd2, hd3, hd4, hd5,
hd6, hd8, hd9var and hd10opt at AIX V5. Syntax of mklvcopy is as
follows:

mklvcopy LVname 2 hdisk1

If user has other paging devices, in addition to hd6, it is recommended
to mirror those as well.

If hd5 consists of more than one logical partition, then, after
mirroring hd5, the user must verify that the mirrored copy of hd5
resides on contiguous physical partitions. This can be verified with
the following command:

lslv -m hd5

If the mirrored hd5 partitions are not contiguous, the user must delete
the mirror copy of hd5 (on hdisk1) and rerun the mklvcopy command for
hd5, using the -m option. The user should consult documentation on the
usage of the -m option for the mklvcopy command.

If rootvg is mirrored using mklvcopy command, the user must manually
synchronize the partitions and disable quorum.

syncvg -v rootvg =>will synchronize all stale partitions
chvg -Qn rootvg =>will disable quorum

To initialize the boot record, run the following:
bosboot -ad /dev/hdisk1

To modify the bootlist, run the following:
bootlist -m normal hdisk0 hdisk1

NOTE: If the system is booted via network, you may need to include the
ent# in the bootlist.

WARNING: Even though this command identifies the list of possible boot
disks, it does not guarantee that the system will boot from the
alternate disk in all cases involving failures of the first disk. In
such situations, it may be necessary for the user to boot from the
installation or maintenance media: select Maintenance, reissue the
bootlist command leaving out the failing disk, and then reboot. On some
models, firmware provides a utility for selecting the boot device at
boot time. This may also be used to force the system to boot from the
alternate disk.

Reboot system to disable quorum, by running either one of the following
commands:
reboot

or
shutdown -Fr


--------------------------------------------------------------------------------

Known problems
AIX 5.3
IY67833 POSSIBLE DATA LOSS OR CORRUPTION AFTER USING CHVG -B OR -G
IY69185 AFTER MIGRATING BIG VG FROM 5.2 TO 5.3, EXTENDVG FAILS
IY71108 EXTENDVG DOES NOT WRITE VGDA TO NEW DISKS

AIX 5.2
IY41715 MKLVCOPY: SUPERSTRICT OPTION DOES NOT WORK AS DISCRIBED IN DOC
IY41740 MKLVCOPY WITH THE SYNCHRONIZE OPTION (-K) WILL HANG
IY37746 ENHANCED CONCURRENT SYNCVG FAILURES WITH I/O
IY40990 CHANGES TO LVCB/ODM NOT PROPAGATED TO REMOTE NODES BY EXTENDLV
OR
MKLVCOPY

AIX 5.1
IY41556 MKLVCOPY WITH THE SYNCHRONIZE OPTION (-K) WILL HANG
IY34117 MKLVCOPY OF LV ON >32 DISKS TO >32 DISKS CAUSES ALLOCP
COREDUMP
IY37229 ENHANCED CONCURRENT MKLVCOPY FAILS WITH 64 BIT KERNEL
IY37897 ENHANCED CONCURRENT SYNCVG FAILURES WITH I/O
IY38022 MKLVCOPY RUNS OUT OF ENVIRONMENT SPACE WITH LARGE LV
IY40939 CHANGES TO LVCB/ODM NOT PROPAGATED TO REMOTE NODES BY EXTENDLV
OR
MKLVCOPY
IY44118 MKLVCOPY FAILS WITHOUT ERROR ON STRIPED LV
IY18954 MKLVCOPY: COMMAND WITH -U AND -S S OPTION FAIL
IY19718 MIRROR LV ACTION GENERATES A NON CONFIRM MKLVCOPY COMMAND
IY40586 MKLVCOPY FAILS FOR 3 COPIES OF STRIPED LV
IY24374 SYNCVG ERROR WITH BAD BLOCK RELOCATION IN CONCURRENT MODE
IY25551 SYNCVG INTERMITTENTLY HANGS
IY25552 SYNCVG -V DOESN'T SYNC ALL PARTITIONS
IY41329 CNTRL-C DURING SYNCVG NOT CLEANING UP
IY45152 SYNCVG FAILS TO SYNC STALE PARTITIONS
IY32881 SYNCVG ON ENHANCED CONCURRENT VG HANGS WITH -P 2 OR HIGHER
IY34959 VOLUME GROUP CORRUPTION AFTER MIGRATION TO AIX 5
IY31649 PPS FAIL TO SYNC ON DISK WITH > 2¬15 PPS
IY37897 ENHANCED CONCURRENT SYNCVG FAILURES WITH I/O
IY45151 SYNCVG FAILS TO SYNC STALE PARTITIONS
IY35272 517 OR 553 LED HANG MINUTES ON SYNCVG ROOTVG IF TCB INSTALLED

AIX 4.3.3
IY11492 MKLVCOPY COMMAND DOES NOT ALLOW -K OPTION IN CONCURRENT MODE
IY06738 MIRRORVG RETURNS DIFF RETURN CODES WHEN RUN TO AN ALREADY
MIRRORED
VG WHEN A DUMP LV IS THERE AND WHEN IT IS NOT THERE
IY24093 SYNCVG ERROR WITH BAD BLOCK RELOCATION IN CONCURRENT MODE
IY30645 PPS FAIL TO SYNC ON DISK WITH > 2¬15 PPs
IY13809 FOR A BIGVG AFTER RMFS <BACKUP> THE LV_AVOID BIT IS NOT
CLEARED
IY21382 SYNCVG -V DOESN'T SYNC ALL PARTITIONS
IY21386 SYNCVG INTERMITTENTLY HANGS
IY11492 MKLVCOPY COMMAND DOES NOT ALLOW -K OPTION IN CONCURRENT MODE

Note:
Fixes can be downloaded from "Quick links to AIX fixes"
(http://www-03.ibm.com/servers/eserver/support/unixservers/aixfixes.html).
For more details regarding any of these APARs, search the Technical
support knowledge base for AIX
(http://techsupport.services.ibm.com/server/aix.srchBroker).



Cross Reference information
Segment Product Component Platform Version Edition
Operating System AIX Installation- backup- restore
Historical Number
isg1pTechnote0607

.

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