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Re: [dm-devel] [PATCH] fix default IO restrictions



Christophe Saout wrote:

I don't think that will happen. The values are already the allowed
maximum values. Or am I wrong?

I don't think they are the max values. SCSI will override them depending on the HBA settings.


Build a DM device from devices on a qla2300 or scsi_debug, and compare the request sizes and merges between accessing the DM device and accessing the SCSI device direclty.


If the table isn't backed by a real device (like if it only contains an error target) the resulting queue will use those "unrealstic" values that exceed the system-wide limits. And a hardsect size of 0 bytes...

If you do not have a device, should you set sane IO restrictions in the target accroding to your target implementation limits.






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