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Removable drive in RT

This article discusses the options for using removable hard drives for a PXI system. I would like to do this with a PXI running RT. The article implies that it is not possible (I would need a rack mount system). Is the article correct?

I want to remove the drive attached to my controller, and boot off a removable drive into RT.The controller is a PXIe-8133; chassis is PXIe-1082, with 4 slots open. Any ideas, anyone?

 

Thanks,

 

Rod

 

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Hello Rod,

 

I have spoken with several engineers that do a lot of work with LVRT, and the response was pretty uniform:  the article you reference is accurate.  For LVRT applications, the only configuration we support for an external boot source is a RAID array.

 

I also asked them about the possibility of using a very large flash drive, and booting off of it.  They strongly recommended against that approach also since USB transfer rates will not likely permit real-time operation.

 

Do you not have easy access to the controller?  For mobility or security concerns, the controller is easily removable, and will take up about the same amount of space (for transportation concerns) as an Express-Card-->eSATA-->HDD setup.

 

Matthew H.
Applications Engineer
National Instruments
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@mudson wrote:

Hello Rod,

 

I have spoken with several engineers that do a lot of work with LVRT, and the response was pretty uniform:  the article you reference is accurate.  For LVRT applications, the only configuration we support for an external boot source is a RAID array.

 

I also asked them about the possibility of using a very large flash drive, and booting off of it.  They strongly recommended against that approach also since USB transfer rates will not likely permit real-time operation.

  



That's not altogether true.  First, LVRT does not support RAID arrays - unless the RAID array controller has an interface to the RT hardware where it looks like a single hard disk (I don't know any of these in existence).  Second, reading from or writing to disk is not considered deterministic anyway - when you boot off a flash disk (supported in RT 2011 and newer, if you know the secret handshake that makes this possible) most everything is loaded into memory, so the access to the disk/USB is fairly minimized.  You're right, there will be a slight performance hit depending on the data operations and what you're trying to do, but it's worth profiling and determining if the performance is still "good enough" for your application.

 

Admittedly, the "real" answer is still the one given - there aren't many RT-compatible means of having "primary removable" storage.  Being able to boot off a USB Flash Drive was done as an "internal" feature in RT 2011 specifically for those who need the ability to have removable storage that does not require a hard disk inside the controller (like a secure facility or somewhere an onboard disk is not needed/desired/allowed) - the same can be said for PXE boot support, which was done for similar reasons.  If you want to give booting a USB Drive with RT a try, contact your local sales rep and they can put you in contact with the RT PSE who can give you the details to try it out.

 

-Danny

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Danny - I went through this last year with a support engineer (booting an 8133 controller into RT with a USB stick) and was successful but only to the point of booting into Safe mode. Couldn't do anything beyond that. I would like to revisit it - can you help me out? Turns out I would also like to do that on a second system.

 

For my original topic, we are just going to consider the whole controller as classified and handle it accordingly, since we need to read and write to a local hard disk.

 

Thanks,

 

Rod

 


TarantulaDiaz wrote:

 

...Being able to boot off a USB Flash Drive was done as an "internal" feature in RT 2011 specifically for those who need the ability to have removable storage that does not require a hard disk inside the controller (like a secure facility or somewhere an onboard disk is not needed/desired/allowed) - the same can be said for PXE boot support, which was done for similar reasons.  If you want to give booting a USB Drive with RT a try, contact your local sales rep and they can put you in contact with the RT PSE who can give you the details to try it out.

 

-Danny


 

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