Solved: Re: Cannot create LUN on a read-only volume or qtree

netappmagic · ‎2013-09-23

I am creating a lun on DR filer, and getting the message as titled. I understand this is because the DR volume is in restric mode,My question is following:
To create a LUN, can I "vol online vol_name", and then after done with creating the lun, do "vol restric vol_name"? Is this how people would do to create a LUN under a restricted DR volume?

Thanks for your inputs

nigelg1965 · ‎2013-09-24

I think you've got yourself a bit confused.

If you're using snapmirror (volume or qtree) you don't need the lun on the target volume, the initial snapmirror does that for you.

snapmirror also copies the entire lun (typically the whole volume) block for block on the initial set up and then any changed blocks on the schedule you set.

In a DR situ you need to mount that lun on the DR server, and will need to have set up the equivalent igroups etc on the DR filer.

View solution in original post

aborzenkov · ‎2013-09-23

What do you call "DR volume"? I have never seen such term in NetApp documentation.

saranraj456 · ‎2013-09-23

I hope you are talking in the terms of volume snapmirror.

if so, once you break the relationship of snapmirror it will make the Volume online and luns will be made available to map.

IPSITAAMAL · ‎2013-09-24

Once you break the snapmirror, the volume will be online automatically and LUN can be created in this Volume. But if you resume the snapmirror again, the DR volume will again be a mirror image of the source volume. I hope I am making my point clear.

netappmagic · ‎2013-09-24

understand all your comments. However, I have one more question.

let's say the volume on primary site is vol1, and dr site is dr_vol1, I created /vol1/lun1, break up the snapmirror on DR site, and then create /dr_vol1/dr_lun1.

Now, my second thought is: how lun1 data is sync'ed to dr_lun1? I understand the entire vol1 including lun1 will be updated to dr_vol1, but how metadata about lun1 is recognized by dr_lun1? Hope you understand what I am saying here.

nigelg1965 · ‎2013-09-24

I think you've got yourself a bit confused.

If you're using snapmirror (volume or qtree) you don't need the lun on the target volume, the initial snapmirror does that for you.

snapmirror also copies the entire lun (typically the whole volume) block for block on the initial set up and then any changed blocks on the schedule you set.

In a DR situ you need to mount that lun on the DR server, and will need to have set up the equivalent igroups etc on the DR filer.

netappmagic · ‎2013-09-24

Hi nigelg1965,

I admit that I am not 100% understanding you.

Do I then need to create the lun on DR site, since data will be replicated anyway in volume basis?

If I need to create the lun on DR site, how does the filer know dr_lun1 will be matching with lun1? it seems to be dr_vol1 has no knowledge on the relationship between dr_lun1 and lun1.

You are absolutely right , that I've got myself a bit confused...

nigelg1965 · ‎2013-09-25

Hi

Once you create the snapmirror relationship and it completes the initial replication, the LUN will be there. What won't be there are the igroup settings.

IPSITAAMAL · ‎2013-09-25

Correct. You don't have to create the lun in DR again, what you need to do is may be create the Igroup and Map the Lun. or if you have already I group is there, map the lun to correct Igroup.

netappmagic · ‎2013-09-25

Okay. So, should I remove the dr_lun1 from DR site then? If I remove it, the lun with the same name as the one on primary site would show up on my DR filer?

aborzenkov · ‎2013-09-25

Yes (adjust volume names of course)

netappmagic · ‎2013-09-26

I used the command "lun destroy /vol/dr_vol1", it gives me the following error, and get the same if I run "lun online /vol/dr_vol1", should I then break the volume first in order to destroy the?

lun online: /vol/dr_vol1 : Read-only file system

IPSITAAMAL · ‎2013-09-27

need few more information

1. Name of the lun that you created on your source filer (specify fullpath for the lun)

2. How did you created the LUN in your DR filer (Did you break the relationship before creating LUN)

3. Name of the lun that you created on your DR filer (Complete path for the LUN)

netappmagic · ‎2013-09-27

ipsita pattanaik, thank you!

after reading your questions, I recognized that I did give names of vol/lun correct here in this post. the following is my answers:

1. on the source filer, lun name: /vol/vol1/lun1

2. I did break the volume first on dr site before created the lun, the lun name i used is the same as on the primary

3. on dr, the same name: /vol/vol1/lun1

as i learnt, i don't need to create the lun on DR site, so, now, i want to remove it, but, it won't allow me to, and getting the message:
lun online: /vol/dr_vol1 : Read-only file system

saranraj456 · ‎2013-09-28

Online the volume and destroy the LUN you want to.Then revert to restrict mode.

IPSITAAMAL · ‎2013-10-03

Hello netappmagic,

Is your issue resolved? were you able to delete the LUN after breaking snapmirror relationship?

netappmagic · ‎2013-10-04

Hello ipsita,

Thanks for checking. I just did it, quiesce and break the snapmirror, and destroy the lun, then resync the snapmirror. the lun has been snapmirrored to DR. Looks all good.

the conclusion is that I have to break the mirror before I can destroy the lun. online volume won't do it. volume has already been online but read-only.

Thanks to all for your help