ORACLE RAC + ServiceGuard, disk/lvol addition

[Juha Eklund_1]

Howdy,
one of our DBA's asked simple question from me:

" We have Oracle RAC cluster ( 3 nodes )with ServiceGuard. We *can't* add disks/lvols to DB without shutting down the shared vg ( and so the total cluster !) Is there any software that will make it possible to add disks to vg and lvol's to DB *without* shutting doen the vg/cluster/db"

I'm not sure but should Veritas Volume Manager ( with some clustering options?) help us to do that in real life?

Have anybody done that in real life ( change from shared SG volume group to Veritas managed volume group + ServiceGuard ) .. If it is possible, how long break we need approximately in real life ( hours ?! The amount of data is about 100 GB )

-- Juha --

[Steven E. Protter]

Shalom Juha,

I'd give myself an 8 hour maintenance window for a shift of that complexity.

Its probably a one hour job, but you want to be able to have some time for unforseen issues.

Its reasonable, since RAC permits shared access of more than one system to the same physical data that you need to down the cluster for this type of work.

Have you looked at the feature set of OnlineJFS? It might be able to help with this.

Shmuel.

[Chauhan Amit]

Hi Juha,

Replies are Inline:

We *can't* add disks/lvols to DB without shutting down the shared vg ( and so the total cluster !) Is there any software that will make it possible to add disks to vg and lvol's to DB *without* shutting doen the vg/cluster/db"

A) You can't accomplish this even with the VxVM

change from shared SG volume group to Veritas managed volume group + ServiceGuard

A) You can use the vxvmconvert utility to convert LVM volume groups into CVM disk groups. Before you can do this, the volume group must be deactivated, which means that any package that uses the volume group must be halted. The procedure is described in Managing Serviceguard user's guide.

Check out below link "Creating a Storage Infrastructure with CVM"

http://docs.hp.com/en/T1859-90017/ch02s07.html#d0e3281

-Amit

[Chauhan Amit]

Also note:

In order to use the VERITAS Cluster Volume Manager (CVM), you need a cluster that is running with a special CVM package. This means that the cluster must already be configured and running before you create disk groups.

-Amit

[Thayanidhi]

Hi,
Tough I have no experiance, the SG-CFS product should have what you are looking for. Contact HP sales team to know more about it. If it's LVM with raw device you can't do it without cluster outage!

Regds
TT

[Juha Eklund_1]

Thanx for quick replies, but I'm still confused ( a little bit ).

Steven: I know the OnlineJFS, but I think thats not an answer ...

Chauhan: You said that even with VXVM one can *not* add disks to VG etc . Do You think that there are *any* solution that will enable tha addon online, without deactivating the VG ( CVM ?! )

Thavanidi: I'll check the SG-CFS ( is it base on Veritas products ) functionality from HP

-- Juha --

[Chauhan Amit]

There i sno other solution I believe.
Let's wait for advice from other Forum members.

-Amit

[rariasn]

Hi Juha,

You can add lvols; no problem.

Copy vg configuration from node active to anothers nodes of the cluster.

ran

[Thayanidhi]

Hi ran,
When the Vg is activasted in shared mode, nothing is possible! even changing the size of the lvols is not possible!!

Juha--
SG-CFS is product to enable JFS funtionality on the shared volumes. If you are using SG-CFS (priced product) you no longer need to have raw volumes!

Regds
TT

[Juha Eklund_1]

Thanx again for information:
>Hi ran,
>When the Vg is activasted in shared mode, >nothing is possible! even changing the >size of the lvols is not possible!!

I agree, that was my feeling also .. I wonder if the designers in the vg-side have at all thouhgth how much it will limit the added value of the cluster if one can *not* make even lvol add-ons to available vg in the fly ..

>Juha--
>SG-CFS is product to enable JFS >funtionality on the shared volumes. If you >are using SG-CFS (priced product) you no >longer need to have raw volumes!
>

Well , I dont mind if there are raw volumes, because Oracle likes them, but if I get with SG-CFS the possibility to add on-fly new lvols , thats all I need ( today )...


>Regds
>TT

-- Juha --