Hello @AnandK 

Thanks for the great question and details. 
We don’t recommend DDB’s sharing disks as they are extreme IO intensive on the disk and if they are fighting for IOPS both are going to suffer. 

That being said there is no reason it would not work and depending on the activity of your environment, size and speed of the disk it could work. If you want to try it and monitoring the Q&I time of the DDB. if you find it going high then move once of the DDB’s to a new disk.

It is very simple to move a DDB so i recommend just testing it. Keep in mind if it works today that does not mean it will work tomorrow. This is a thing you will have to monitor and take action when it becomes an issue. This is why our recommendation is DDB’s don't share disks.

Kind regards

Albert Williams

Hi @AnandK 

From the description it seems that there will be a storage policy with Primary and 2 selective copies.

All copies are using these 3 disks that you mentioned in their respective datapaths. Although all disk are attached to the same MA.

If the above configuration is what we are looking at, then every copy will have its own DDB. We cannot share DDB within the same storage policy.

Let me know if I did not get it rt.

Thanks.

 Hello @Abhishek Narulkar 

I understood the question that the author understands there will be multiple DDB’s but can they be hosted on the same disk. But you are 100% correct. Each library will have its own DDB and we recommend they be on their own disks. 

Kind regards

Albert Williams

Hi @Albert Williams 

As you mentioned about the DDBs being IO intensive, to maintain the high DDB QI performance, we should try to have those hosted in separate disk only.

So as @AnandK  mentioned,

configure individual DDB disk