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converting legacy filesystem to persistent filesystems and viceversa

laiju.c.babu
Regular Advisor

converting legacy filesystem to persistent filesystems and viceversa

Hi Team,

 

Currently we are using legacy filesystems (/dev/dsk/ctd) for creating vgs. Now we want to convert existing vgs to persistant device files . Is this is possible without data loss. And one more thing if i convert once to persistant device files then can i convert back those vgs to legacy type.

 

Could any one please help me on this

 

Regards

Laiju C Babu

Laiju.C.Babu
8 REPLIES
Torsten.
Acclaimed Contributor

Re: converting legacy to persistent device special files

Just use "vgdsf" to convert the lagy to persistant device special files within LVM.


Hope this helps!
Regards
Torsten.

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laiju.c.babu
Regular Advisor

Re: converting legacy to persistent device special files

Hi Torsten,

Thanks for the reply,

 

Could you please tell me can i convert back this to legacy again

Laiju.C.Babu
Torsten.
Acclaimed Contributor

Re: converting legacy to persistent device special files

vgdsf is a script that basically extends the persistant files and reduces the legacy.

 

So you can do the same to revert back - but IMHO there is absolutely no reason to do this.


Hope this helps!
Regards
Torsten.

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laiju.c.babu
Regular Advisor

Re: converting legacy to persistent device special files

Hi Torsten,

 

But i didnt see any option in vgdsf to rollaback to legacy..

 

We are in a planning stage of this . So i want if any thing goes wrong is there any chance for roll back to legacy.

 

 

Laiju.C.Babu
Torsten.
Acclaimed Contributor

Re: converting legacy to persistent device special files

Basically the script does something like

# vgextend vg__ /dev/disk/disk__

# vgreduce vg__ /dev/dsk/cxtydz

and so on ...

so you can do the same to revert back - but it will never be needed.

With 11.31 you should use the persistant device files as standard.

Hope this helps!
Regards
Torsten.

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

__________________________________________________
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laiju.c.babu
Regular Advisor

Re: converting legacy to persistent device special files

Hi Torsten,

 

Thanks for your time .  Using vgdsf i converted legacy to persistant device files...

 

Then as you told , for roll back i extended the vg to all legacy files then i reduced the vg from the persistent device files...

 

There was no data loss. and we can do it online also .......

 

Regards

Laiju 

Laiju.C.Babu
laiju.c.babu
Regular Advisor

Re: converting legacy to persistent device special files

Hi Torsten,

 

Could you please tell me what are the advantages of  using  persistant  device over legacy

 

Regards

Laiju

Laiju.C.Babu
Torsten.
Acclaimed Contributor

Re: converting legacy to persistent device special files

The most important advantage IMHO is you have only 1 device file per LUN, not up to 8 or even more.

Let's assume you have 10 LUNs on multiple paths, now you have 10 device files, in the past you could have 80 paths or more.

Hope this helps!
Regards
Torsten.

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

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