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Go Back  dBforums > Database Server Software > DB2 > Steps to split a primary database to use it as standby database

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Old 03-04-10, 08:00
amit_nsharma amit_nsharma is offline
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Red face Steps to split a primary database to use it as standby database

Hi,

I am quite new to DB2 world.

I need to split a primary database to use it as standby database.

I am aware of the following steps:
1) Suspend I/O on the primary database
2) Use appropriate operating system-level commands to split the mirror or mirrors from the primary database
3) Resume I/O on the primary database
4) Catalog the mirrored database on the secondary system
5) Start the database instance on the secondary system
6) Initialize the mirrored database on the secondary system using db2inidb
7) etc etc

Problem is I am not aware of executing the step number: 2

I am using OS as SuSE 10u2. I am not using any external memory device
I have 2 different machine of SuSE 10u2 and need to configura 1 as Primary database and second as Standby database.

Can you please help me with proper steps to execute and create split mirror of the database and import it as standby database on another machine ?

Please correct me if I am wrong anywhere.
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Old 03-04-10, 08:24
ARWinner ARWinner is offline
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What DB2 version are you using?

What is your intention for the standby system?

Andy
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Old 03-04-10, 09:39
n_i n_i is offline
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"Split mirror" operation must be supported by your storage subsystem. Talk to your storage administrator. If I were you I'd choose the backup method of setting up HADR.
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Old 03-04-10, 23:12
amit_nsharma amit_nsharma is offline
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Quote:
Originally Posted by ARWinner View Post
What DB2 version are you using?

What is your intention for the standby system?

Andy
I am using Db2 version 9.7

My objective for creation of standby database is to configure High Availability mode between the two DB2 servers.
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Old 03-04-10, 23:23
amit_nsharma amit_nsharma is offline
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Quote:
Originally Posted by n_i View Post
"Split mirror" operation must be supported by your storage subsystem. Talk to your storage administrator. If I were you I'd choose the backup method of setting up HADR.
I am not using any special storage subsystem. I just need to copy split Db on another machine or shared location.
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Old 03-04-10, 23:45
Marcus_A Marcus_A is offline
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Quote:
Originally Posted by amit_nsharma View Post
I am not using any special storage subsystem. I just need to copy split Db on another machine or shared location.
I have done what you want to do using a Hitachi SAN subsystem which specifically has support for the doing a split mirror, and they supplied the commands to do the split. As mentioned above, this has to be supported by your storage vendor to the best of my knowledge. If there is some kind of generic support at the OS level, I am not aware of it, unless you could do something with RAID 10 and split volumes that way.

Starting with DB2 9.7 FP1 there is support for read only access on the HADR standby with isolation level UR. However, you will have to fully license the standby server in that case, instead of the 100 PVU charge if the HADR standby does not have read access activated.
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Old 03-05-10, 08:19
ARWinner ARWinner is offline
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This is what happens in a split mirror:

1) Suspend Writes on the database server - This means that no writes to disk are allowed. All applications wanting to write data will wait until the write suspend is canceled
2) The entire database files are copied to the target system. How long this takes depends on the disk system
3) Write suspend is canceled. Users can write data again.


The problem is step 2. It needs to happen real fast (< 1 second is optimal). If it does not happen quickly then you have users calling you at all hours because the system is not working in their eyes. That is why there is special hardware/software to perform this task. Without the special hardware, the only way to copy the entire database to the target is with an OS copy command. This will be very slow as the target is a remote system. Most shops cannot afford for the system to periodically "hang" for long periods of time.

Since you are using conventional hardware, you need to look elsewhere for you HADR needs.

Andy
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