>>>>> "Mike" == Mike Christie <michaelc@xxxxxxxxxxx> writes: Mike> If you are just trying to get to 1MB, then instead of enabling Mike> clustering we could also increase the defaul Mike> SCSI_MAX_PHYS_SEGMENTS. It is 128 now, but there is a compile Mike> option to set it it up to 256. I have essentially been having the same problem doing big direct I/Os using sg. I ended up bumping sg_tablesize to 1024 but only because I knew the controllers used for this application support that many scatter-gather segments. As you mention, SG_ALL is 255 and that used to be the max value (quite useless, just short of 1MB). In recent kernels it's been clamped to 128 thanks to getting intimate with the block/request layer. These short lists are quite useless for contemporary tape hardware that need a block size of 1MB at the minimum and preferably 2MB or more... -- Martin K. Petersen Oracle Linux Engineering - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
