The procedure for replacing a faulty disk mechanism depends
on the type of disk configuration you are using. Separate descriptions
are provided for replacing an array mechanism and a disk in a high
availability enclosure.
Replacing a Faulty Array Mechanism |
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With any HA disk array configured in RAID 1 or RAID 5, refer
to the array's documentation for instruction on how to
replace a faulty mechanism. After the replacement, the device itself
automatically rebuilds the missing data on the new disk. No LVM
activity is needed. This process is known as hot swapping
the disk.
Replacing a Faulty Mechanism in an HA Enclosure |
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If you are using software mirroring with MirrorDisk/UX (non-OPS
data only) and the mirrored disks are mounted in a high availability
disk enclosure, you can use the following steps to hot plug
a disk mechanism:
Identify the physical volume name of
the failed disk and the name of the volume group in which it was
configured. In the following examples, the volume group name is
shown as /dev/vg_sg01 and the physical volume name is shown as /dev/c2t3d0.
Substitute the volume group and physical volume names that are correct
for your system.
Identify the names of any logical volumes that have
extents defined on the failed physical volume.
On the node on which the volume group is currently
activated, use the following command for each logical volume that has extents on the failed physical volume:
# lvreduce -m 0 /dev/vg_sg01/lvolname /dev/dsk/c2t3d0 |
At this point, remove the failed disk and insert
a new one. The new disk will have the same HP-UX device name as
the old one.
On the node from which you issued the lvreduce
command, issue the following command to restore the volume group
configuration data to the newly inserted disk:
# vgcfgrestore /dev/vg_sg01 /dev/dsk/c2t3d0 |
Issue the following command to extend the logical
volume to the newly inserted disk:
# lvextend -m1 /dev/vg_sg01 /dev/dsk/c2t3d0 |
Finally, use the lvsync
command for each logical volume that has extents on the failed physical volume. This
synchronizes the extents of the new disk with the extents of the
other mirror.
# lvsync /dev/vg_sg01/lvolname |
Replacing a Lock Disk |
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Replacing a failed lock disk mechanism is the same as replacing
a data disk. If you are using a dedicated lock
disk (one with no user data on it), then you need to issue only
one LVM command:
# vgcfgrestore /dev/vg_lock /dev/dsk/c2t3d0 |
After doing this, you should reinitialize the cluster lock
by either halting and restarting one of the nodes in the cluster
using cmhaltnode followed by cmrunnode
or else by halting and restarting the entire cluster, using cmhaltcl
followed by cmruncl.
Online Hardware Maintenance with In-line SCSI Terminator |
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MC/LockManager allows online SCSI disk controller hardware
repairs to all cluster nodes if you use HP's in-line terminator
(C2980A) on nodes connected to the end of the shared FW/SCSI bus.
The in-line terminator cable is a 0.5 meter extension cable with
the terminator on the male end, which connects to the controller
card for an external bus. The in-line terminator is used instead of
the termination pack that is attached to the controller card and
makes it possible to physically disconnect the node from the end
of the F/W SCSI bus without breaking the bus's termination. (Nodes
attached to the middle of a bus using a Y cable also can be detached
from the bus without harm.) When using in-line terminators and Y
cables, ensure that all orange-socketed termination packs are removed
from the controller cards.
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 | NOTE: You cannot use inline terminators with internal FW/SCSI
buses on D and K series systems, and you cannot use the inline terminator
with single-ended SCSI buses. You must not
use an inline terminator to connect a node to a Y cable. |
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Figure 8-1 “F/W SCSI Buses with In-line
Terminators ” shows a three-node
cluster with two F/W SCSI buses. The solid line and the dotted line
represent different buses, both of which have inline terminators
attached to nodes 1 and 3. Y cables are also shown attached to node
2.
The use of in-line SCSI terminators allows you to do hardware
maintenance on a given node by temporarily moving its packages to
another node and then halting the original node while its hardware
is serviced. Following the replacement, the packages can be moved
back to the original node.
Use the following procedure to disconnect a node that is attached
to the bus with an in-line SCSI terminator or with a Y cable:
Move any packages on the node that requires maintenance to
a different node.
Halt the node that requires maintenance. The cluster
will re-form, and activity will continue on other nodes. Packages
on the halted node will switch to other available nodes if they
are configured to switch.
Disconnect the power to the node.
Disconnect the node from the in-line terminator
cable or Y cable if necessary. The other nodes accessing the bus
will encounter no problems as long as the in-line terminator or
Y cable remains connected to the bus.
Replace or upgrade hardware on the node, as needed.
Reconnect the node to the in-line terminator cable
or Y cable if necessary.
Reconnect power and reboot the node. If AUTOSTART_CMCLD
is set to 1 in the /etc/rc.config.d/cmcluster file, the node will
rejoin the cluster.
If necessary, move packages back to the node from
their alternate locations and restart them.
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