Replace SSA disk in Mirror

[chrisw669]

I have a dead hdisk in my ssa array that needs to be replaced. it's been so long since i've done this i forgot the command syntax to remove the disk.

i have 14 disks mirrored, hdisk2-hdisk8 are mapped together and hdisk10-hdisk16 are together then they 2 sets mirror each other.

should i do a
rmlvcopy <lvname> 1 hdisk10
or
rmlvcopy <lvname> 1 hdisk10 hdisk11 hdisk12 hdisk13....

 

[chrisw669]

[tt]
here's some more info....
# lsvg -l datavg
datavg:
LV NAME TYPE LPs PPs PVs LV STATE MOUNT POINT
rd jfs 205 410 14 open/stale /rd
db jfs 1294 2588 14 open/stale /db
fix010 jfs 173 346 14 open/stale /FIX010
loglv00 jfslog 1 2 2 open/stale N/A
dbbackup jfs 945 1890 14 open/stale /dbbackup
sort jfs 1133 1133 14 open/syncd /sort


# lslv -m db |pg
db:/db
LP PP1 PV1 PP2 PV2
0001 0132 hdisk5 0132 hdisk14
0002 0132 hdisk6 0132 hdisk15
0003 0132 hdisk7 0132 hdisk16
0004 0132 hdisk8 0133 hdisk13
0005 0133 hdisk3 0132 hdisk10
0006 0133 hdisk4 0133 hdisk11
0007 0133 hdisk2 0133 hdisk12
0008 0133 hdisk5 0133 hdisk14
0009 0133 hdisk6 0133 hdisk15
0010 0133 hdisk7 0133 hdisk16
0011 0133 hdisk8 0134 hdisk13
0012 0134 hdisk3 0133 hdisk10
0013 0134 hdisk4 0134 hdisk11
0014 0134 hdisk2 0134 hdisk12
0015 0134 hdisk5 0134 hdisk14
0016 0134 hdisk6 0134 hdisk15
0017 0134 hdisk7 0134 hdisk16
0018 0134 hdisk8 0135 hdisk13
0019 0135 hdisk3 0134 hdisk10
and so on.....
[/tt]

 

[bi]

Here's my two cents' worth. I hope some of the gurus will either confirm or tell me I'm nuts:

You should be able to just replace the disk and then sync the logical volumes. You don't have to break the mirror to replace the disk.

From you description, it looks as if you are using these disks as system disks, rather than as members of an SSA array. So, I think what you need to do is:

rmdev -ld hdisk10

Then, put the new disk in the enclosure. Run cfgmgr to get the system to recognize the new physical disk.

Designate the pdisk as a system disk. Assuming these are the only disks in the system (other then hdisk0 and hdisk1), the hdisk designation should automatically be hdisk10. Then, just sync the LVs.

 

[KenJM]

I believe that you do have to break the mirror.

rmlvcopy <lv name> 1 hdiskn hdiskn1 etc

This will then allow you to remove the hdisk from the vg

reducevg <vgname> hdisk10

Remove the hdisk from the odm

rmdev -l hdisk10 -d

and the pdisk

rmdev -l <pdiskn> -d

Problems I've had when the disk isn't removed first causes a new disk ID to be created by the system as the old one still exists in the ODM. Can be tidied up afterwards but by then the new disk is in with a new number.

Good luck

 

[donttreadonme]

smitty ssaraid
change member disk in ssa array
remove disk from ssa raid array

diag
task selection or service aids
ssa service aid
set service mode and identify
(select disk to be removed)
set service mode
(remove disk from loop then replace)
set service mode and identify (re-establish loop)

rmdev -dl pdiskXX
cfgmgr
lsdev -Cc pdisk

change show use of ssa physical disk
choose option array candidate disk
(F3 back to ssaraid array screen)
change member disks in ssa raid array
add disk to array
(choose pdisk number of new disk)
(array will begin rebuild)
(to check the state of array)
change show attributes of ssa raid array
(will show percentage completion)

 

[bi]

If you do have to break the mirror, and assuming the dead disk is hdisk10, shouldn't the command be:

rmlv <lvname> 1 hdisk2 hdisk3 ...hdisk8

This will leave a copy on hdisk2 through hdisk8, right?

 

[KenJM]

BI,
I Don't think so. As far as I can remember the rmlvcopy reduces the number of copies to the number specified <1> destroying the copies on the disks specified.

Happy to hear other pepes interpretations though....

KjM

 

[donttreadonme]

Good luck ChrisW.

Looking at the posts you can see why forums are not always useful.

 

[apb99]

This is the process i have used for logical volume mirrored disk, with success

Replacing SSA disk after it has failed

Basic Overview

1. identify the disk and the resources that use it
2. remove this disk from any volume groups safely so it is not used anywhere ( this may also mean removing other disks from the configuration aswell )
3. isolate the disk within the SSA loop
4. remove the disk definitions
5. remove and replace the disk
6. configure the new disk onto the rs6000 this should have the same pdisk and hdisk as the old disk
7. add to the volume group
8. add to logical volumes and re-mirror and sync volumes


Procedure

1. Check which disk and what it is allocated to it

Normally you have the pdisk number :

Translate pdisk/hdisk ssaxlate –l pdisknnn
Find out volume group lspv | grep hdisknnn
List logical volumes lspv hdisknnn –l
List disks in logical volume lslv lvname –l
List ppartition mapping lslv lvname –m | pg or lslv lvname -m > filename

You also need to know the physical location .. a serial number is useful as the disks have these on the front .. if you have a disk mapping document you maybe able to locate the tray and location from this or use either of the following

diag -- enter -- task selection -- SSA service aids --
link verfication and the the ssa card select the pdisk and hit enter to set identify and note serial number or set service mode find the pdisk set the service mode and note the serial number


maymap -a -h this will report on all SSA loops and what is on it with the hdisk number and serial numbers

If this is part of a HACMP sysytem or where this disk is connected to multiple systems you need to check the other systems, is the disk in use ... what are the pdisk and hdisk names for it ... use the pvid number to track the disk between systems

2. remove disk from logical volume

run rmlvcopy for each logical volume allocated to that disk and remove all disks for that mirror copy

3. remove disk from volume group

run reducevg command for failed disk on the volume group

4. run diag

use ssa service aids ….. set service mode to identify the pdisk this will cause the LED onthe front to flash and isolate the disk in the loop ready for hot swap

5. physically replace disk, then reset service aids to ensure service mode is off

6. remove definition of pdisk and hdisk from box and odm

rmdev-dl hdisknnn
rmdev –dl pdisknnn

7. Now configure new disk
cfgmgr

8. Check new disk hdisk number ( hopefully the same as before ) lspv | grep None

9. add to volume group

extendvg vgname hdisknnn

10. now re make logical volume copies

use mklvcopy add 1 more copy to all disk as before for all logical volumes needed( this sometimes can be complex if a disk is allocated to more than one logical volume then a map
file can be used to ensure that the partition mappings across disk mirrors are correct, )

The allocation map file contains records specifying the exact physical partitions to allocate to the logical volume. Records are in the form: PVnamePnum1[-PPnum2], where PVname is the physical volume name and PPnum is the physical partition number. Use one record for each physical partition or each range of consecutive physical partitions.
Partitions are used in the order given in the MapFile. Used partitions are skipped.

11. sync logical volumes

syncvg –l lvname

Note : once the logical volume copies are reduced to 1 until the syncvg commands have finished you have no mirroring, if a logical volume uses more that 2 disks in its mirror you increase the risk of data loss through another disk failure once you remove all the mirror disks from a logical volume.