serviceguard mirror

 
juan ramos_1
Advisor

serviceguard mirror

Hi all
I have a cluster with a volume group with one disk and its mirror disk, I want to replace one of the disk on the volume group that is reporting error to the syslog, I want to know if I can replace the disk while the cluster is up.
Thanks for any Tips.
8 REPLIES 8
Geoff Wild
Honored Contributor

Re: serviceguard mirror

Sure - of course you can - for the most part:

1) If the disk is completely "dead", such as if you run ioscan and status is "no_hw" then you can hot swap the disk online.

2) However in circumstances where the disk has not fully failed please do one of the following to avoid data corruption :

a) reduce mirror before replacing the disk
b) deactivate VG before replacing the disk
c) shutdown system to replace the disk

Rgds...Geoff

Proverbs 3:5,6 Trust in the Lord with all your heart and lean not on your own understanding; in all your ways acknowledge him, and he will make all your paths straight.
Sundar_7
Honored Contributor

Re: serviceguard mirror

Juan,

You can replace the disk as long as the disk is hot swappable.

1) Hot swap the failed disk
2) do a ioscan and confirm the system is able to see the disk with HW STATUS as CLAIMED
3) do a vgcfgrestore and restore the LVM conf to the new disk

# vgcfgrestore -n /dev/vgname /dev/rdsk/cXtYdZ
# vgsync /dev/vgname


- Sundar


Learn What to do ,How to do and more importantly When to do ?
Prashant Zanwar_4
Respected Contributor

Re: serviceguard mirror

Hot swapping is meant to be for that purpose or if have internal array mirroed disk then also you shall be able to replace without disturbing anything.

if it is lvmmirrored, do as sundar has said.

Thanks

Prashant
"Intellect distinguishes between the possible and the impossible; reason distinguishes between the sensible and the senseless. Even the possible can be senseless."
juan ramos_1
Advisor

Re: serviceguard mirror

Thanks all for the responses.
the disk is accesible, sometimes it reports error to the syslog, I want to replace it before it definitely crash.The disk enclousure is hotswap, tell me if I can use this procedure with the package running :

lvreduce -m 0 /dev/vg01/lvol1
vgreduce /dev/vg01 /dev/dsk/c4t0d0
replace the disk (c4t0d0)
pvcreate /dev/rdsk/c4t0d0
vgextend /dev/vg01 /dev/dsk/c4t0d0
lvextend -m 1 /dev/vg01/lvol1 /dev/dsk/c4t0d0

Geoff Wild
Honored Contributor

Re: serviceguard mirror

Actually, you can do a vgcfgrestore:

vgcfgrestore -n /dev/vg01 /dev/rdsk/c4t0d0

vgsync /dev/vg01

Rgds...Geoff
Proverbs 3:5,6 Trust in the Lord with all your heart and lean not on your own understanding; in all your ways acknowledge him, and he will make all your paths straight.
Sridhar Bhaskarla
Honored Contributor

Re: serviceguard mirror

Hi Juan,

There is a simple process for that.

1. Replace the disk. Run ioscan -f and make sure the disk is claimed on both the nodes.
2. Do a 'vgcfgrestore'

vgcfgresotre -n vgxx /dev/rdsk/cxtydz
vgchange -a e vgxx (or use the activation mode you use in serviceguard)

3. vgsync vgxx

That should sync up the mirrors.

-Sri
You may be disappointed if you fail, but you are doomed if you don't try
PC_7
Frequent Advisor

Re: serviceguard mirror

you might want to look at technical knowledge base doc id UMCSGKBRC00008685 (attached).

Hope this helps.
Sandeep Kapare
Advisor

Re: serviceguard mirror

The configuration details for a given VG are asored in /etc/lvmconf/VG??.conf file. If you are planning to remove the defective disk out of the volume group (i.e. you are not going to replace it with a good one) only then you need to do vgreduce. Else, the process is preety simple as mentioned by others -
Swap the disk with a good one.
Do ioscan -fnCdisk (& make sure new disk is seen)
do a vgcfgrestore & vgsync.
Your volume is back to its original state.
Nothing is impossible