Queue Depth in DT tool

[bdinesh86wdc]

It’s been very long time, Hope you are doing good ?

I am working on tape devices and I am using DT tool to validate the tape functionality and other things as well.

Here is my quick question, how do we run with higher QD on tape devices using DT tool in any Linux flavours OS ? if the tool doesn’t allow as of now, how to achieve it ? is there an option that you could think of ?

Any sort of answers from you will be a bigger help for us.

Thanks,
Dinesh Babu

[RobinTMiller]

Hi Dinesh, dt has tape support, but is conditionalized out by default. Actually, I have not tested tapes for over ~15 years. Tapes don't have a queue depth. dt uses POSIX AIO to keep tapes streaming. Are you testing virtual tapes which are actually disks on the backend per chance? If the latest dt has issues with tapes, I can locate an older version (I think). Regards, Robin

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__________________________________________________________________________________ "I'm not where I want to be, but thank God I'm NOT where I used to be!" --Joyce Meyer

On Mar 18, 2020, at 3:01 AM, bdinesh86wdc ***@***.***> wrote:  It’s been very long time, Hope you are doing good ? I am working on tape devices and I am using DT tool to validate the tape functionality and other things as well. Here is my quick question, how do we run with higher QD on tape devices using DT tool in any Linux flavours OS ? if the tool doesn’t allow as of now, how to achieve it ? is there an option that you could think of ? Any sort of answers from you will be a bigger help for us. Thanks, Dinesh Babu — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[bdinesh86wdc]

Hi Robin,

As you guessed, we are using VT (virtual tapes ) which are HDD drives in the backend. I wanted to run I/Os on VT devices with some number of QDs. so it is possible ? i read in DT user guide, which says Qdepth is allowed only in HP-UX OS alone. So is there are way to implement QDepth in any linux flavour OS ?

Latest DT doesn't have any issues, it is working fine.

sorry for disturbing you a lot.

Thanks,
Dinesh Babu

[RobinTMiller]

The HP-UX support was to set the queue depth dynamically. dt uses the OS set queue depth. Multiple threads or AIO drive multiple IO requests. Cheers, Robin

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__________________________________________________________________________________ "I'm not where I want to be, but thank God I'm NOT where I used to be!" --Joyce Meyer

On Mar 18, 2020, at 6:55 PM, bdinesh86wdc ***@***.***> wrote:  Hi Robin, As you guessed, we are using VT (virtual tapes ) which are HDD drives in the backend. I wanted to run I/Os on VT devices with some number of QDs. so it is possible ? i read in DT user guide, which says Qdepth is allowed only in HP-UX OS alone. So is there are way to implement QDepth in any linux flavour OS ? Latest DT doesn't have any issues, it is working fine. sorry for disturbing you a lot. Thanks, Dinesh Babu — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or unsubscribe.