asked on

gsclvmd and lazy update on powerha

Hi,

I have read gsclvmd is used on ECVGs to synzronize LVM's ODM on both nodes of the cluster and lazy update process is when the ONLINE node is gone and the second import all VGs updating its ODM with all changes. but my question is if gsclvmd and lazy update are the same?

Does gsclvmd daemon does importvg VGs on the passive node's ODMs?

Thanks much!

SOLUTION

woolmilkporc

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

SOLUTION

woolmilkporc

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

sminfo

ASKER

jee.. believe me wmp... it's really confusing!! I haven't found which tasks from LVMs do gsclvmd for example... On the other hand lazy_update/fast_take_over I swear it was the same... I have to go home now.. I'll reply on a copule of hours (I have to study tonight! ;)

ASKER CERTIFIED SOLUTION

woolmilkporc

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

sminfo

ASKER

WMp.. my confusion begans when, at work, we migrate all clusters from ECVGs-2nodes to ECVGs-3nodes-2sites-GLVM.. all problems began here because there's no LVM's synchronization between nodes... Look an example:

Yo have worked on node1 for 1 year, you have extendlv, create/delete LV, create/delete FS, ect etc... so, all these changes are not syncronize to node2 and node3. (All this was confirmed through PMRs with IBMs)... so, if you stop cluster services without moving it to node2 an node3 just before the stop.. yo MUST exportvg/importvg VGs on node2 and node3 changing RPVs just to synchronize data... believe or not?

Yes, as you hear, unbelievable that an HA application have to be stopped for exportvg/importvg to synchronize all changes between nodes...

So, I wanted to look how powerha/hacmp LVMs syncronization worked.. and that's the questio...

BTW, I have read this chapter of the redbook and, if I don't forget, it talks about changes on the gsclvmd's log (alog)...

And now I think you're right about lazy update is NOT fast disk takeover...

I need to create my own lab with theses clusters to look answers by my own..

Thanks!!

woolmilkporc

>> these changes are not syncronize to node2 and node3 <<

This is quite normal if you neither use CSPOC to make the changes nor have EC VGs.

CSPOC does lazy update, as we know in the meantime, and EC does fast takeover.

If neither of the above mechanisms are used - how should the cluster manager know what you did with the VGs? Only node1 will know, the other nodes will stay on the level set during the first importvg.

>> I have read this chapter of the redbook <<

You should have scrolled down a bit. The chapter which deals with the logs is 4.9.3 ("The gsclvmd daemon log"). Chapter 4.10 ("Group Services Concurrent LVM enhancements") lists various conditions and their consequences (yes, logging is among these consequences, but not only).

Thx for the points! Once you have your own lab we'll turn the tables and I'll start asking you for help.

Best wishes,

wmp

sminfo

ASKER

wmp... "the points" are nothing compare with your help and explanations all over these years ago...... This forum, and special with your knowledge, have help me to learn, understand and troubleshoot this wonderful OS since from June/2010 when I start working with AIX...

I'll let you know when the lab is OK...

See ya!