On Tue, 4 Feb 2025, Martin K. Petersen wrote: > > Mikulas, > > > If there is some particular SSD that has more write IOPS for 8k requests > > than for 4k requests, I'd like to know about it - out of curiosity. > > SSD blocks are getting bigger and bigger, some drives hide it better > than others. Also look at all the efforts going on wrt. supporting > larger block sizes in the kernel. > > Can you send me the output of: > > # sg_vpd -p bl /dev/sdN > > and maybe hdparm -I too? I'd like to see if we can come up with a > reasonable heuristic. > > -- > Martin K. Petersen Oracle Linux Engineering I don't have that USB-SATA bridge that reports optimal I/O size 65535 sectors. Milan talked about it, but maybe he doesn't have it too. Some user reported that cryptsetup behaves badly with this particular bridge, so Milan wrote workaround for it in cryptsetup. You can simulate it with "modprobe scsi_debug dev_size_mb=32 sector_size=512 num_tgts=1 opt_blks=65535" Mikulas
