MHVTL via FC using SCST Target

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MHVTL via FC using SCST Target

[nia]
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 MHVTL via FC using SCST Target

Postby tomkat183 » Sat Mar 20, 2010 2:37 pm

I wish if I had a couple of Qlogic FC HBA's to test this but I wonder if anyone else had the hardware to test MHVTL via FC using SCST Target ?

Tom K.
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Re: MHVTL via FC using SCST Target

Postby rami766 » Sat Mar 20, 2010 2:48 pm

Can buy cheap used FC cards from ebay ? I am planning for this one day.
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Re: MHVTL via FC using SCST Target

Postby eric0e » Tue Apr 06, 2010 3:14 am

I was able to get mhvtl + scst to work with a Qlogic QLA2342 card. I am using the svn version of scst downloaded on 2-Apr-2010. Base OS is Ubuntu 9.04 32bit server with a 2.6.33.1 kernel and the recommended scst kernel patches. I am using the QLA2300 firmware that came with Ubuntu 9.04. My client systems (scsi initiator) are running RHEL 5u4 and using QLA2342 cards. The FC switch is a Brocade 3250.

Eric
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Re: MHVTL via FC using SCST Target

Postby nia » Tue Apr 06, 2010 4:07 pm

I was able to get mhvtl + scst to work with a Qlogic QLA2342 card


Eric, this is very cool .. Did you have any diffeculties setting this up ? What about performace ? .. I do not know if you have tried the iSCSI version yet but I suspect SAN target is faster.

I was wondering if you have time to post a detailed write up for this ;) 

Thanks


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Re: MHVTL via FC using SCST Target

Postby eric0e » Wed Apr 07, 2010 2:32 am

It was time consuming to get it to work. On a 500 MHz system, compiling a kernel takes about 5 hours, and it took a few tries to get it working. Right now I have not done any performance testing, just functionality testing. It has only been running for a couple of days and I need to get the functionality part tested for a project that I am working on. On a 500 Mhz system with a single PATA drive, I am not expecting much performance, but I need a FC library, or something that looks like one, for the project. My load on the system is >4 when running 4 tape drives, probably due to having compression set to 3.

I am seeing an issue with a kernel thread dying in the Qlogic driver when it goes into target mode, but it does not seem to be causing any problems in using the driver. It may be an issue with my old hardware. I have ordered a used 2.2 GHz system with more RAM, and if I see the same kernel thread issues with that hardware, I will submit a bug to the scst team. 

I am exporting both the mhvtl and several vdisks LUNs over FC. I have multiple clients accessing the vdisk LUNs as part of a SAN shared file system. So far I have had no data-corruption issues with the mhvtl or disk LUNs, and no issues with the software. I am using the mhvtl dev branch, using the April release.

I have crude notes that I hope to refine when I load the new system. I used several of the scripts from or pointed to in the “iSCSI-SCST + Centos 5.4 + MHVTL 0.18-4 STEP BY STEP” post and generated a couple of my own. As I’m still figuring out scst, my scripts are probably doing things the hard way.

Eric
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