SCSI Pass Through Mode on native fiber tape library

[Won_Choi]

I have a Dell PV 132T LTO3 library running a native fiber tape drive unit. I have not been getting a satisfied through put results. I am only getting around 600 MB.min instead of max through put 1.2 GB/min(???). I would like to know disabling Write SCSI through Mode would increase the performance.

[Ken_Putnam]

No, that would not affect performance See http://support.veritas.com/docs/259030

Are you getting errors on the tapes?

From the devices tab, properties for the drive, What are the settings for

Block size
Buffer Size
Number of buffers

Also, verify that neither "Single Block" option is selected

[Won_Choi]

No tape errors.

Block Size (per deivce) 64k
Buffer Size (per device) 64k
Buffer Count 10
High Water Count 0

I unchecked both read and write single block mode.

[Ken_Putnam]

Those look OK, tho I would probably set the buffer to either 128 or 256KB

If the Single Block options were previously selected, you should notice a marked improvement in throughput now

[Won_Choi]

Thank you for your inputs. I will give it a try tonight.

[Won_Choi]

Would it impact anything if the libary is in a shared storage environment? The LTO3 library is connected to the SAN via fibre switch.

[shweta_rege]

Hello,


Do you also receive any event ids in the event logs?




Thank You,


Shweta

[Ken_Putnam]

read through the TechNote I listed before. Pass-Through SHOULD be used on a SAN environment, but it is for handling error detection and reporting

[Rucha_Abhyankar]

Hi Won,


Please let us know if the earlier suggestions were helpful.

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