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MSL Libraries to Media Server Ratio

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Occasional Contributor

MSL Libraries to Media Server Ratio

Is there any docs out there identifying the media server to tape drive or library ratio? We are trying to identify if we need to purchase another media server to improve performance and need to have numbers to justify for or against it.

Frequent Advisor

Re: MSL Libraries to Media Server Ratio

I've never seen such a document, but here's the best hints I can give.

The primary limits I can think of are going to be your connections to the tape drives and the network.

Assuming you are using fibre channel connectivity, the math says to get best performance from LTO1 drives is no more than 3 drives, or 2 LTO2 drives, or 1 LTO3 drive, per 2GB FC connection. In practice you can probably do 4 LTO1. An LTO4 drive requires a 4GB FC connection per drive.

For network, that's going to be based on the number of objects you are streaming to the media server at any given time, and the overall performance of the network.

Memory, I think there might be something in the main administrator's guide about that. CPU you'll have to monitor.

In other words...start throwing more backups at the current media server until backup speed starts dropping off.

My experience is all MSL & EML, over fibre channel connections via a full fabric (interconnected switches).

Our config also has most servers having their own connections to the fabric, and thus each server is its own Media Server. The size of our backups (100s of GB up to 2.4 TB per server) doesn't give us room to do it over the network.
Occasional Contributor

Re: MSL Libraries to Media Server Ratio

Thanks for the reply. Points me in a good direction to justify expenditures by pointing to the hardware limits alone.