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Need to create a cascaded business copy

 
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Derek Brown
Frequent Advisor

Need to create a cascaded business copy

Hi

I've looked at the manuals for this and I'm still confused. Hoping someone here can help me create a horcm config file that will allow me to create a cascaded BCV.

I've attached here our existing horcm0.conf and horcm1.conf . These files are working and in production so I need to be careful not to screw them up otherwise my head will be on the block !

Everything is happening within the same server (urrtw01b) so there is no need to consider any other servers here. horcm0.conf essentially defines the same sets of data 3 times (bcv1, bvc2, bvc3) and horcm1.conf defines the luns that this data is replicated to.

As you will know, you can only create 3 sets of L1 pairs so I've used up my limit. I now need to create a L2 pair (ie a cascade or leaf) which I need to be a copy of the BCV3 data. This is where I am stuck.

I think I may need to create a horcm2.conf to define this and maybe also make additions to horcm0.conf but I'm not sure. Could someone possibly amend and/or create me the entries I need in the horcm config files please then that will be enough for me to figure out the logic of how it works and also allow me to do the job! I'd be eternally grateful.

Here are the luns (CU:Ldevs) that have been allocated to me to create the cascade ; lets call it bcv4 for convenience :

09:00
09:01
09:02
09:03
09:04
14 REPLIES 14
Prashanth Waugh
Esteemed Contributor
Solution

Re: Need to create a cascaded business copy

Hi

Which storage you r using like xp10000,12000 etc

Reagrds
Atul

For success, attitude is equally as important as ability
Derek Brown
Frequent Advisor

Re: Need to create a cascaded business copy

Hi

XP12000

regards

Derek
Prashanth Waugh
Esteemed Contributor

Re: Need to create a cascaded business copy

Hi
For success, attitude is equally as important as ability
Prashanth Waugh
Esteemed Contributor

Re: Need to create a cascaded business copy

Hi ,

Pls check the doc it will give some idea.
you closed thethread .its solved or not.sorry I m not able to attachethe doc.
----------------------------------------
Cascade function
This function creates a second layer of volume pairs underneath the first layer of BC pairs. Pairs created
in the first and second layer are called cascaded pairs. Figure 12 illustrates cascaded BC volume pairs.
The first cascade layer (L1) is the original BC pair, consisting of one P-VOL (root volume) and up to three
S-VOLs (node volumes). In the second cascade layer (L2), the S-VOLs of the original BC pair function as
the P-VOLs of the L2 pairs, and each L2 P-VOL can have up to two S-VOLs (leaf volumes). This layering
scheme can create up to nine copies of one BC primary volume (P-VOL).
Every volume can have up to three Mirror Unit (MU) numbers associated with it. The MU number
designates a pair for which the volume is a member. The MU number is not the number of the pair, but
the number of the volume. A pair is made up of two volumes of which each pair member could have the
same or different MU numbers.
├в ┬в MU=0 is the number of a volume for its first pair.
├в ┬в MU=1 is the number of the same volume for its next pair.
├в ┬в MU=2 is the number of the same volume for its third pair.
├в ┬в The MU number of an S-VOL is always MU=0.
34 Business Copy XP (BC) for the Array
For Level 1 (L1) pairs, the root volume could have MU=0, MU=1, and MU=2. For L1 pairs, the associated
S-VOLs all have MU=0 because this is the first pair of which they are a member.
For the Level 2 (L2) pairs, the L1 S-VOLs are now all acting as L2 P-VOLs. Because they are already a
member of one pair, the next MU number for each of them is MU=1 for their first L2 pair and MU=2 for
their second L2 pair. For the S-VOLs associated with each of these pairs, the MU number is once again
MU=0 because this is the first pair of which they are a member.

Reagrds
atul



For success, attitude is equally as important as ability
Derek Brown
Frequent Advisor

Re: Need to create a cascaded business copy

Atulkumar

It's very nice of you to cut and paste a piece of a manual for me that describes the functionality of cascading business copies ; but that is not what I need.

I need to know the exact configuation changes/additions to the files I attached in my original post and also whether or not I need to create a new horcm2.conf file on top of my existing horcm0.conf and horcm1.conf files.

Can you provide this information please ?
thanks
Derek
Prashanth Waugh
Esteemed Contributor

Re: Need to create a cascaded business copy

Hi Derek,

When you are going to implement this change.
I am thinking on it how to achive this.

Reagrds
atul
For success, attitude is equally as important as ability
Derek Brown
Frequent Advisor

Re: Need to create a cascaded business copy

Hi,

Wednesday next week.

thanks

Derek
cjb_1
Trusted Contributor

Re: Need to create a cascaded business copy

Derek

I don't believe there is anything to stop you making another BC from one of your original copies providing the data doesn't change. You wouldn't need a horcm2.conf just amend the current horcm0.conf and horcm1.conf.

So, to horcm0.conf add:
stby2_bcv4 erp3-1 60188 0b:00 0
stby2_bcv4 erp3-2 60188 0b:01 0
stby2_bcv4 erp3-3 60188 0b:02 0
stby2_bcv4 erp3-4 60188 0b:03 0
stby2_bcv4 erp3-5 60188 0b:04 0

stby2_bcv4 urrtw01b horcm1

And horcm1.conf
stby2_bcv4 erp3-1 60188 09:00
stby2_bcv4 erp3-2 60188 09:01
stby2_bcv4 erp3-3 60188 09:02
stby2_bcv4 erp3-4 60188 09:03
stby2_bcv4 erp3-5 60188 09:04

stby2_bcv4 urrtw01b horcm0

We do something similar across multiple hosts.
Derek Brown
Frequent Advisor

Re: Need to create a cascaded business copy

Chris,

Thanks for that but unfortunately that type of config is not possible.

The rules of business copy creation state that you can only create 3 copies from the original. If you want more than that (a 4th in my case) then you have to use the cascade method i.e. take a copy from a copy.

So I'm trying to obtain the config changes I need to make/add to my existing config files to allow a cascaded copy. If you know how to do that then I'd appreciate your help.

Derek