Re: Integration of SCST in the mainstream Linux kernel

[david@lang.hm]

On Fri, 8 Feb 2008, Vladislav Bolkhovitin wrote:

>>> 2. I think, everybody will agree that Linux iSCSI target should work over 
>>> some standard SCSI target framework. Hence the choice gets narrower: SCST 
>>> vs STGT. I don't think there's a way for a dedicated iSCSI target (i.e. 
>>> PyX/LIO) in the mainline, because of a lot of code duplication. Nicholas 
>>> could decide to move to either existing framework (although, frankly, I 
>>> don't think there's a possibility for in-kernel iSCSI target and user 
>>> space SCSI target framework) and if he decide to go with SCST, I'll be 
>>> glad to offer my help and support and wouldn't care if LIO-SCST eventually 
>>> replaced iSCSI-SCST. The better one should win.
>> 
>> 
>> why should linux as an iSCSI target be limited to passthrough to a SCSI 
>> device.
>> 
>> the most common use of this sort of thing that I would see is to load up a 
>> bunch of 1TB SATA drives in a commodity PC, run software RAID, and then 
>> export the resulting volume to other servers via iSCSI. not a 'real' SCSI 
>> device in sight.
>> 
> David, your question surprises me a lot. From where have you decided that 
> SCST supports only pass-through backstorage? Does the RAM disk, which Bart 
> has been using for performance tests, look like a SCSI device?

I was responding to the start of item #2 that I left in the quote above. 
it asn't saying that SCST didn't support that, but was stating that any 
implementation of a iSCSI target should use the SCSI framework. I read 
this to mean that this would only be able to access things that the SCSI 
framework can access, and that would not be things like ramdisks, raid 
arrays, etc.

David Lang