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Mounting HDD from One system to another

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Malps
Advisor

Mounting HDD from One system to another

Hi,

Due to Hardware failure one of my server is down.Now I have connected 2 HDDs(It has data in it) from that server to Another live server.Both the servers are HP-UX RX-2620.

when I do "ioscan -fnC disk" ,I get following output for the new disks on the Live Server,

disk 4 0/1/1/0.1.0 sdisk NO_HW DEVICE HP 36.4GST336754LC
/dev/dsk/c2t1d0 /dev/dsk/c2t1d0s2 /dev/rdsk/c2t1d0 /dev/rdsk/c2t1d0s2
/dev/dsk/c2t1d0s1 /dev/dsk/c2t1d0s3 /dev/rdsk/c2t1d0s1 /dev/rdsk/c2t1d0s3
disk 6 0/1/1/1.2.0 sdisk CLAIMED DEVICE HP 73.4GST373454LC
/dev/dsk/c3t2d0 /dev/dsk/c3t2d0s2 /dev/rdsk/c3t2d0 /dev/rdsk/c3t2d0s2
/dev/dsk/c3t2d0s1 /dev/dsk/c3t2d0s3 /dev/rdsk/c3t2d0s1 /dev/rdsk/c3t2d0s3

Now please help me in mounting these HDDs as when I try to mount them using following command it gives me error

# mount /dev/dsk/c3t2d0 /newdisk
/dev/dsk/c3t2d0: unrecognized file system

Certainly I am making a mistake somewhere & as it is apparent I am not clear about the basics when it comes to mounting HDDs.

Please let me know what are the steps when it comes to Mount HDDs like this.

Thanks In Advance :-)

D

20 REPLIES
R.K. #
Honored Contributor

Re: Mounting HDD from One system to another

Hi Malps,

We CANNOT mount HDD.

Do you want to access the data in them or just want to use them afresh?
Please explain your purpose of mounting these HDDs?
Don't fix what ain't broke
Malps
Advisor

Re: Mounting HDD from One system to another

Yes,

I want to make the data accessible from those disks.

That is the reason I have removed it from the server which is down & connected them to this server.

Pls Suggest How can I access the data in those Disks.Does it involve creating a Volume Group of these disks to mount them?As I am new to LVM Concept I am unsure of the steps to take as the Data needs to be safegurded.

Thanks!!
Kanagaraj
Regular Advisor

Re: Mounting HDD from One system to another

Hi Malps,

you can not mount RAW HDD,for mounting HDD---> need to create LV ( before pvcreate + add into vg )& creating File system then only you can mount that LV. (On Sun server you can mount slices separately) But HP you can not mount like that...

But your case,Already running server got down and both disk has data and you want to use that??

If I am not wrong,both the servers are same model, then try to boot from failed machine HDD on running machine for that you need to remove it's own disks(for safety/identification).It is risk one.(make sure already datas backed up)

hope you are unerstand? ..
R.K. #
Honored Contributor
Solution

Re: Mounting HDD from One system to another

Hi Again..

Following are the steps to do this. But for these steps you require mapfile of that VG which contained these disks in down server from /etc/lvmconf directory. You must be having the backup of VG00 of the down server (to extract /etc/lvmconf/mapfile_of_VG)



1. Create a new directory for the volume group you are importing:

# mkdir /dev/vgxx

2. Make a group character device file for the group. The 01 in the
device file corresponds to the 01 in the minor number (i.e.,
they should be the same):

# mknod /dev/vgxx/group c 64 0x0N0000


3. # insf -eC disk

4. # ioscan -fnC disk << identify new disks and they should be CLAIMED

5. You need to transfer it to the /etc/lvmconf directory on the new system before you issue this command:

# vgimport -s -v -m /dev/vgxx

This adds the volume group and its disk to the target system.
The Physical Volumes are scanned to obtain the Volume Group
information and Logical Volume information.


6. Activate the volume group:

# vgchange -a y /dev/vgxx


7. Make a mount point directory in the root directory for each logical
volume in the newly imported volume group:

# mkdir /dir_name1

8. # mount /dev/vgxx/lvol_name /dir_name1

9. Backup the lvm configuration
# vgcfgbackup /dev/vgxx
Don't fix what ain't broke
Malps
Advisor

Re: Mounting HDD from One system to another

Hi R.K.

Thanks for a Quick Response,I really Appreciate it.

I am not sure how to access /etc/lvmconf on that server as it is Already down.

How would I know whether the backup of vg00 is available & if it is there on these two disks ,how can I access it?

R.K. #
Honored Contributor

Re: Mounting HDD from One system to another

Backup NOT in the HDD...Check if you have tape backup of VG00 of the down server...if yes...we can connect that tape to any running server and extract /etc/lvmconf/vgxx.map
Don't fix what ain't broke
Malps
Advisor

Re: Mounting HDD from One system to another

Hi R.K.


I do have a Tape back up.

I will check that.

Will late you know the Update.

Thanks a Lot for your Assistance.
R.K. #
Honored Contributor

Re: Mounting HDD from One system to another

Hi..

Try doing above steps as it is, only making changes to STEP 5. Make it:
# vgimport -v /dev/vgxx /dev/dsk/cxtydz

If you don't use mapfile with vgimport, Logical Volume names are created on the target system using the default naming convention lvol## where ## is the Logical Volume minor number. I hope that should not bother you a lot, as you require only the data.
Don't fix what ain't broke
Malps
Advisor

Re: Mounting HDD from One system to another

ok.

Thats is my only concern.

I just need that data.I wont be backing it up somewhere else but would be accessing it from this new server from now onwards.

So does that mean It is ok if I dont have the mapfile?

If yes,I will try the steps right away instead of searching for that mapfile on the tape?

Thank You!
R.K. #
Honored Contributor

Re: Mounting HDD from One system to another

Sure....you can try this now.
Don't fix what ain't broke
Malps
Advisor

Re: Mounting HDD from One system to another

Hi R.K.
As you said

5. You need to "transfer" it to the /etc/lvmconf directory on the new system before you issue this command:
# vgimport -v /dev/vgxx /dev/dsk/cxtydz

What do you mean by "transfer to /etc/lvmconf" directory on the new system?

Also can I use following command

# vgimport -v /dev/vg01 /dev/dsk/c2t1d0 /dev/dsk/c3t2d0

As I want to make these two disks (/dev/dsk/c2t1d0 & /dev/dsk/c3t2d0) a part of volume group vg01.

Thank You!
R.K. #
Honored Contributor

Re: Mounting HDD from One system to another


>>You need to "transfer" it to the /etc/lvmconf directory

Since we are not using mapfile.....so no need to transfer the file from tape to running server.

Yes..use below command if both these disks were in same VG in down server.
# vgimport -v /dev/vg01 /dev/dsk/c2t1d0 /dev/dsk/c3t2d0
Don't fix what ain't broke
Torsten.
Acclaimed Contributor

Re: Mounting HDD from One system to another

Solution is easy.

You did

# mount /dev/dsk/c3t2d0 /newdisk

but the disk is a bootable disk, all the data is in partition 2, so you need to mount the "s2" part:

# mount /dev/dsk/c3t2d0s2 /newdisk

Hope this helps!
Regards
Torsten.

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Torsten.
Acclaimed Contributor

Re: Mounting HDD from One system to another

Sorry, the command was nonsense.

You need to vgimport both "s2" devices, then mount the lvols.

Hope this helps!
Regards
Torsten.

__________________________________________________
There are only 10 types of people in the world -
those who understand binary, and those who don't.

__________________________________________________
No support by private messages. Please ask the forum!

If you feel this was helpful please click the KUDOS! thumb below!   
Malps
Advisor

Re: Mounting HDD from One system to another

Hi R.K.

The Issue is finally resolved.

I thanks a lot for your timely help.

Please suggest any good readings so that I can be confident as far as LVM is concerned!

Bye Take Care!!!
Johnson Punniyalingam
Honored Contributor

Re: Mounting HDD from One system to another

Hi Malps,

check Below Thread for , LVM documentation

http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1259562397968+28353475&threadId=446311

Finally .. Please D'not forget to assign points for people who help to resolve your problem.

0 points for my post.

Thanks,
Johnson
Problems are common to all, but attitude makes the difference
R.K. #
Honored Contributor

Re: Mounting HDD from One system to another

Hi Malps..

Attached a doc for LVM which discusses some common activities done in LVM.

Regds..
Don't fix what ain't broke
R.K. #
Honored Contributor

Re: Mounting HDD from One system to another

Another troubleshooting doc that might be helpful for you.
Don't fix what ain't broke
Malps
Advisor

Re: Mounting HDD from One system to another

Hey Thanks R.K.

This all seems a lot of Information as of now!!

Thanks for sharing!!

Cheers!
Kanagaraj
Regular Advisor

Re: Mounting HDD from One system to another

Always close the thread,once your problem resolved.