device file name after putting SAN switch in between server and storage

[kirit_2]

Hi

I need to confirm whether device file naming will change or not in following case with some logic.

existing configuration:
one L3000 and one rp4440 server connected directly to CX500 EMC storage ( fiber cable directly connected from storage to server)

- 8 LUNs are created in CX500 storage and 4 volume groups are configured on it.

New configuraiton:

- Two nos of brocade switches will be installed in between servers and CX500 storage


- please confirm the same asap.

[Torsten.]

The device files *will* change, because you'll get a different HW path to the storage.

Be prepared to vgexport and later vgimport your VGs.

[kirit_2]

Hi Torsten

Can you please let me know some procedure.

what exact command need to use for vgexport and vgimport

- do i need to keep copy of some of the files which will help in case of any problem while vgimport

[Pete Randall]

I would run vgexport in preview mode:

vgexport -p -s -m /tmp/vg01map /dev/vg01

Then, after connecting through the switch, run vgimport like this:

vgimport -s -m /tmp/vg01map /dev/vg01

The -s option will scan the devices and determine which ones make up vg01 (or whatever vg you are working with).


Pete

[kirit_2]

Hi

I need to confirm - do I need to run #vgexport after creating map files for VGs , as -p option only does preview of vgexport but doesnt actually do vgexport from the system , so when I will try to do vgimport it might say vg is already there

- please confirm this

[sysadm_1]

yes you have to do vgexport otherwise system will not allow to import same VG again.

after creating map file,

1.umount all volumes in that vg
2.vgchange -a n vgxx
2.vgexport /dev/vgxx

After connecting the switches,

1.find the new path using

ioscan -fnCdisk
insf -e

2.mkdir /dev/vgxx
mknod /dev/vgxx/group c 64 0x0xxxxx
vgimport -m mapfile /dev/vgxx /dev/dsk/cxtxdx (one of the new path to LUN)

3.vgchange -a y vgxx

4.mount -a (if the new vg name is different,u have to modify /etc/fstab accordingly)


-sysadm-

[kirit_2]

Hi

can I use map file created earlier with option -m -s -p -v so that I dont need to specify physial volumes while importing it?

- also does #vgexport removes any configuration from disk ?

[sysadm_1]

New Disk names ar edifferent.Then how can you use the same old disk names for importing VG.

vgexport will not remove anything from disk.It removes VG entry from /etc/lvmtab and removes folder /dev/vgXX and update the lvm configuration.

Before doing vgexport,i suggest you to save a copy of
/etc/lvmtab
/etc/fstab

Outputs of following commands
bdf
ioscan -fnCdisk
ls -l /dev/vgXX


-sysadm-