I have some basic questions about disk mirroring. Now my customer
is doing disk mirroring as following.
Internal Disk Internal Disk
+-----------+ +-----------+
| +-------+ | | +-------+ |
| |OS(AIX)| | Mirroring | |OS(AIX)| |
| +-------+ | <============> | +-------+ |
| +-------+ | | +-------+ |
| | Data1 | | | | Data1 | |
| +-------+ | | +-------+ |
+-----------+ +-----------+
hdisk0 (1GB) hdisk1 (1GB)
(In above, Data1 is a filesystem for application data and OS includes
some filesystems like /usr, /home, /tmp....)
My customer is planning to add a external 2GB disk to this RS/6000
because of increasing data and now we are considering following
disk configuration for adding external 2GB disk. (Of course we
have to do disk mirroring.)
Internal Disk External Disk
+-----------+ +-----------+ +----------------------+
| +-------+ | | +-------+ | | +-------+ +-------+ |
| |OS(AIX)| | | | Data2 | | Mirroring | |OS(AIX)| | Data2 | |
| +-------+ | | +-------+ | <========> | +-------+ +-------+ |
| +-------+ | | +-------+ | | +-------+ +-------+ |
| | Data1 | | | | Data3 | | | | Data1 | | Data3 | |
| +-------+ | | +-------+ | | +-------+ +-------+ |
+-----------+ +-----------+ +----------------------+
hdisk0 (1GB) hdisk1 (1GB) hdisk2 (2GB)
(In above, Data1, Data2 and Data3 are several filesystems for
application data.)
RS/6000 model 360 with AIX V3.2.3Eup
hdisk0 ==> 1.0GB SCSI Disk Drive (Internal disk)
hdisl1 ==> 1.0GB SCSI Disk Drive (Internal disk)
hdisk2 ==> 2.0GB SCSI Disk Drive (External disk)
My questions are following.
Q1) Can we configure above disk allocation? Especially, can we do
disk mirroring in above environment?
Q2) I tested them using RS/6000 model 520 and 9333 serial-link disk.
And I could make copies of each LV using mklvcopy command and invoke
syncvg command without problem.
(My customer's external disk is 2GB SCSI disk drive.)
However when I created boot device on the 9333 disk, following error
messages were displayed.
----------------------------------------------------------------------
# mklv -y hd5x -t boot -a e rootvg 2 hdisk3
hd5x
# bosboot -a -l /dev/hd5x -d /dev/hdisk3
0301-164 bosboot: Boot image is 11225 512 byte blocks.
0514-218 bootlist: the device hdisk3 cannot be used to boot from
because
the system ROS does not support it
0301-163 bosboot: bootlist failed with hdisk3.
0301-165 bosboot: WARNING¢ bosboot failed - do not attempt to boot
device
----------------------------------------------------------------------
In above,
RS/6000 model 520 with AIX V3.2.5
hdisk0 ==> 670 MB SCSI Disk Drive (Internal disk)
hdisk1 ==> 355 MB SCSI Disk Drive (Internal disk)
hdisk3 ==> 1.07GB Serial-Link Disk Drive (External disk : 9333)
I guess that we cannot boot from 9333 disk because 9333 is not
SCSI device.
Q3) Is this correct? If not, is there any problem in our configuration?
ANSWER
You should be able to perform disk mirroring according to
your diagram just fine. Follow the procedures outlined in
fax# 2587 Mirroring the rootvg Volume group for AIX 3.1 or
3.2 (obtainable by calling 1-800-IBM-4FAX).
You can only boot off of a 9333 from certain hardware.
Unfortunately, the 520 is an older model and is not among the
hardware that has the ROS boot info for serial drives.
In general in order to boot from a 9333 you must have
hardware with a ROS level of p/n 43G2189 or later.
This ROS level can only be found in the following machines:
7011-220
7012-340, 350
7013-580
7013-970, 980
or those systems annnounced and manufactured later than these.
These machines use a 512K segmented EPROM ROS and use XIO. The
older machines only have a 128K EPROM ROS. Any newly announced
systems manufactured after April 20, 1992 should have this
level or a higher level of ROS.
Also, you must have the following ptfs to provide boot support
for the 9333 if you are less than AIX 3.2.5:
U402101 Required for 1.07GB Serial Disk Drive
U402381 Required for Boot/Install of 9333 Disk System
U403243 Required microcode changes for 9333 Disk Systems
You will probably need to find an alternative to using
the 9333 as a boot device.
Thanks very much for your answer. Your answer is very useful for
me. Please allow me to ask a little more.
In following case, when the hdisk0 is crushed, do we need to
re-coufigure hdisk1? (Of course I know that we have to change
disk and re-configure hdisk0 at that time.)
In other words, if one of internal disks is crushed, does another
internal disk work correct?
Internal Disk External Disk
+-----------+ +-----------+ +----------------------+
| +-------+ | | +-------+ | | +-------+ +-------+ |
| |OS(AIX)| | | | Data2 | | Mirroring | |OS(AIX)| | Data2 | |
| +-------+ | | +-------+ | <========> | +-------+ +-------+ |
| +-------+ | | +-------+ | | +-------+ +-------+ |
| | Data1 | | | | Data3 | | | | Data1 | | Data3 | |
| +-------+ | | +-------+ | | +-------+ +-------+ |
+-----------+ +-----------+ +----------------------+
hdisk0 (1GB) hdisk1 (1GB) hdisk2 (2GB)
(In above, Data1, Data2 and Data3 are several filesystems for
application data.)
Thanks very much in advance.
ANSWER
If hdisk0 is damaged, hdisk1 does not need to be reconfigured.
The data is intact on the logical volume level (i.e. filesystem).
If this drive goes bad you will have to use the "rmlvcopy" command
to remove the mirrored LVs on hdisk0. Then use the "reducevg"
command to remove the disk out of the VG and then use the "rmdev"
command to remove the definition of the disk from the system and
then replace the disk. After this procedure then just remake the
mirrors that you have lost the way that you created them in the
beginning and your system will be back to normal.
Thank you.
S e a r c h - k e y w o r d s:
9333 MIRRORING BOOT
WWQA: ITEM: RTA000086176 ITEM: RTA000086176
Dated: 04/1995 Category: ITSAI6000GE
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