lvmpvg

[Roger Baptiste]

hi,

How many of you specify alternate links in the lvmpvg file. If so, I would like to know the restrictions/issues in specifiying alternate paths in /etc/lvmpvg file.

I understand that, not specifying alternates
is also fine. But, since there are systems which already have them, i want to ensure they are set correctly.

For instance, The doc KBRC00001507 mentions that , if alternates are listed in the lvmpvg file, they should be in the same order in which they are listed in the group.
Then, another doc 1653284992 mentions the specifying alternates could lead to data corruption and panics.

So, what is the definitive opinion on this??

thanks
-r

[James R. Ferguson]

Hi:

I declare my alternate links in the appropriate order in my /etc/lvmpvg file. They are declared *after* their primary counterparts simply because that makes sense and is additonal documentation.

I read the two references you cited but cannot, at the moment, deduce why failure to order the links appropriately would lead necessarily to corruption. If I recall correctly, if you have an /etc/lvmpvg file with primary and alternate links and proceed to swap them (vgreduce, vgextend) I *don't* believe that the file is updated to reflect the swap.

Regards!

...JRF...

[Martin Burnett_2]

Hello,

The document you referred to 1653284992 is a bit dated. At one time it was not advisable to put your alternate links into the lvmpvg. The problem (large Free PE values) and more than one LE pointing to the same PV/PE were the result of having both links to a PV in the lvmpvg file. In fact, at the time if you used the commands (vgcreate/vgextend) to setup the lvmpvg file they would put both links into it.

But an SR was opened and a Patch issued (PHCO_17389 at the time) resolved this issue. This patch has since been superseded and the issue was corrected in subsequent releases.

Martin