Create a symbolic link in the root fs of a VDM

Question

I have the following configuration on a unified vnx 5600:

nas_version: 8.1.9-211

VDM name: agntssflg01

interface configured & attached to VDM to support NFS exports

new 1GB filesystem created & mounted to vdm as /TSS

export created: agntssflg01:/TSS

What I want to do, is create a new symbolic link in the root filesystem of the VDM named /ABC that has the target of /TSS

normally, on any linux server, for local application/use access, I would do this as: #ln -s /TSS /ABC

Can the same thing be done on a VDM?

My constraints (self imposed & developer imposed) are:

I would prefer to not create multiple filesystems & mount them at the needed paths

I would prefer to not create the export on the physical DM

The developer needs 9-12 exports for testing, with a space need of a few MB (thus creating multiple 1GB minimum size for each export is a waste of space)

All the exports needed on the VDM follow the format of: 'agntssflg01:/<3 letters>'

All the exports need to available (which means i can't remove/re-add the filesystem to each one as needed/scripted)

I have tried to mount the same filesystem again at a different mount point, but that didn't work

Rainer_EMC · Answer

I would suggest to try the -name option of server_export aka. NFS aliasing It should do what you want and create a symlink that can be used as an alternate path to the export

Scott_K99 · Answer

Thanks Rainer,

That works for creating 1 of the 9-12 exports I need.

I was able to create one(1) additional name and access it remotely, but when I tried creating a 3rd entry for hte name, it overwrote the 2nd one I created.

original export:

#server_export agntssflg01 -P nfs -ignore -o access=adminhost:10.x.y.0/24,root=adminhost:10.x.y.0/24 -comment "dev export 1" /TSS

1st alias added:

server_export agntssflg01 -P nfs -name "ABC" -ignore -o access=adminhost:10.x.y.0/24,root=adminhost:10.x.y.0/24 -comment "dev export 1" /TSS

from admin host:

[root@adminhost ~]# showmount -e agntssflg01

Export list for agntssflg01:

/TSS 10.x.y.0/24

/ABC 10.x.y.0/24

3rd alias added:

server_export agntssflg01 -P nfs -name "DEF" -ignore -o access=adminhost:10.x.y.0/24,root=adminhost:10.x.y.0/24 -comment "dev export 2" /TSS

from admin host:

[root@adminhost ~]# showmount -e agntssflg01

Export list for agntssflg01:

/TSS 10.x.y.0/24

/DEF 10.x.y.0/24

So it almost works the way I need.

Anything else I can try ?

Rainer_EMC · Answer

I guess it was designed with one alias in mind - I never tried using more than one

you can try to create the symlinks on the rootfs through /nas/quota

Note that AFAIR this following of the symlinks might not work with NFSv4

Other option would be to fix on the client side by using automounter

Scott_K99 · Answer

So last night I was trying to figure out how to get to the root VDM, because if I could get to the root where the exports start from, I can create symbolic links at the root to subfolder in the filesystem & export those.

After reading/googling/looking on the VNX, I figured out that I could mount the DM root filesystem to the control station:

#mount server_2:/ /mnt/vdm20

In there, I could see the folder structure for the VDMs (e.g. root_vdm_##)

Looking into the root_vdm_20 folder (which matches the VDM i needed this on), I found the new filesystem mounted as /TSS

Poking around, in the .etc folder, i found the vdm.cfg file for the exports.

Short version, is I was able to create softlinks to subfolders inside the /TSS mount

#ls -s /root_vdm_20/TSS/

once those were created, I was able to create new exports to the symlink

#server_export agntssflg01 -P nfs -o access=10.x.y.0/24:adminhost,root=10.x.y.0/24:adminhost /

From my adminhost, i was able to see all the new exports, mount them as nfsv3, read/write data to them.

For the developers, this is what they wanted.

Rainer_EMC · Answer

glad it worked

make sure you test this with NFSv4 as well - if your developer systems use it

P.S.: please to dont change anything in .etc - these arent config files that are meant to be edited - they need to be in sync with other places like NASDB

Scott_K99 · Answer

Thanks Rainer.

Yeah, I did not change any of those files, just poked around looking at that folder structure & contents of files.

The view of the root_vdm_20 folder looks like this now:

[root@agzquavnx03-cs0 root_vdm_20]# ls -lha

total 32K

drwxr-xr-x 4 root bin 1.0K Dec 6 17:13 .

drwxr-xr-x 40 root bin 3.0K Nov 21 21:06 ..

lrwxrwxrwx 1 root root 29 Dec 6 17:03 ABC -> /root_vdm_20/TSS/ABC

lrwxrwxrwx 1 root root 20 Dec 6 16:57 DFS -> /root_vdm_20/TSS/DFS

lrwxrwxrwx 1 root root 24 Dec 6 16:58 EFG -> /root_vdm_20/TSS/EFG

lrwxrwxrwx 1 root root 29 Dec 6 17:01 DF1 -> /root_vdm_20/TSS/DF1

lrwxrwxrwx 1 root root 29 Dec 6 17:01 DF2 -> /root_vdm_20/TSS/DF2

lrwxrwxrwx 1 root root 29 Dec 6 17:01 DF3 -> /root_vdm_20/TSS/DF3

lrwxrwxrwx 1 root root 29 Dec 6 17:01 DF4 -> /root_vdm_20/TSS/DF4

lrwxrwxrwx 1 root root 29 Dec 6 17:01 DF5 -> /root_vdm_20/TSS/DF5

lrwxrwxrwx 1 root root 29 Dec 6 17:13 DF6 -> /root_vdm_20/TSS/DF6

drwxr-xr-x 10 root root 1.0K Nov 21 20:58 .etc

lrwxrwxrwx 1 root root 20 Dec 6 17:09 PRD -> /root_vdm_20/TSS/PRD

drwxr-xr-x 16 root root 1.0K Dec 6 10:32 TSS

[root@agzquavnx03-cs0 root_vdm_20]#

where the TSS folder is the the only mounted filesystem in the VDM.

VNX

Create a symbolic link in the root fs of a VDM

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