Sandra Inderbit Absent Member.
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Concurrency; Block size, Segment size, Disk agent buffers

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I would like to install a MSL8096 with 3 x SAN 4GB LTO-4 drives.
Could someone tell me, how I have to set the Concurrency, the block size, segment size and the disk agent buffers?
It's important that we can read also LTO-2 Tapes.

OS: Windows 2003 SP2 / R2
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Shoghi Martinez Absent Member.
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Re: Concurrency; Block size, Segment size, Disk agent buffers

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If you have differents block sizes, you can always create diferents DP devices with diferents configurations but pointing to the same physical drives.
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Eemans Dany Absent Member.
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Re: Concurrency; Block size, Segment size, Disk agent buffers

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Hi,

Reading LTO 2 tapes reading in an LTO 4 tapedrive is possible.
The only point that is importend is to know the block size on which they are formatted.

By default this is 64 KB. When your LTO4 drive is set to 64KB this should not be a problem.

This setting can be found at drive properties >> settings >> advanced.

Dany
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Sandra Inderbit Absent Member.
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Re: Concurrency; Block size, Segment size, Disk agent buffers

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Thank you Dany. But how I have to set the Concurrency, segment size and the disk agent buffers?

Thanks
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Shoghi Martinez Absent Member.
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Re: Concurrency; Block size, Segment size, Disk agent buffers

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If you have differents block sizes, you can always create diferents DP devices with diferents configurations but pointing to the same physical drives.
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Shoghi Martinez Absent Member.
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Re: Concurrency; Block size, Segment size, Disk agent buffers

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Concurrency is specified on the backup specification in the destination tab,

You can change the agents buffers value while configuring a new device or when changing the device properties using the Advanced options for the device, although this is rarely necessary. Acording with the DP documentation There are two basic reasons to change this setting:

Shortage of memory: the shared memory required for a Media Agent can be calculated as follows: DAConcurrency*NumberOfBuffers*BlockSize
Reducing the number of buffers from 8 to 4, for instance, results in a 50% reduction in memory consumption, but also results in the creation of performance implications.

Streaming: If the available network bandwidth varies significantly during backup, it is important that a Media Agent has enough data ready for writing to keep the device in the streaming mode. In this case, you should increase the number of buffers.

HTH
Shoghi.

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