On 24 March 2018 at 00:19, Jason Sirichoke <jason.sirichoke@xxxxxxxxxxxx> wrote: > > I am trying to run a test to a device that only supports UNMAP commands > but not TRIM. So I am able to use sg_unmap successfully but it looks like > the trim commands sent by FIO fail as unsupported > > Is there a way to easily configure or modify FIO to send UNMAP instead of > TRIM? These commands should be functionally very close to each other so > was hoping this might be possible. In short not unless you were to add the code to perform this to the sg ioengine (where sending raw SCSI commands makes sense). Many ioengines can cope with the generic block layer but at that layer you don't know the disk below is truly a SCSI one (it might be SATA, NVMe etc). The UNMAP command is specific to SCSI and even then only certain SCSI disks - some SCSI disks implement unmapping via the WRITE SAME command... It's a pity your "SCSI disk" doesn't expose what's required for Linux to enable discard (which is what regular fio engines are using to do trim) and it might be worth your while quickly checking why. The last time I ran into that situation was with old ESXi which didn't advertise enough feature (see https://stackoverflow.com/a/40817859/9109338 ). -- Sitsofe | http://sucs.org/~sits/ -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
