On 28.02.2019 10:48, Ilia Zykov wrote: >> >> Well, there are the following 2 commands: >> >> Get physical block size: >> blockdev --getpbsz <device> >> Get logical block size: >> blockdev --getbsz <device> >> >> Filesystems seem to care about the physical block size only, not the logical >> block size. >> >> So as soon as you have PVs with different physical block sizes (as reported >> by blockdev --getpbsz) I would be very careful... > > Hello everybody. > Maybe, I don’t understand what do you mean. What the logical block size > mean? But on my machines(CentOS7), this utility get me the strange > results (output reduced): > > smartctl -i /dev/sda; blockdev --getbsz --getpbsz /dev/sda > Device Model: INTEL SSDSC2KB480G8 > User Capacity: 480,103,981,056 bytes [480 GB] > Sector Sizes: 512 bytes logical, 4096 bytes physical > Rotation Rate: Solid State Device > 4096 > 4096 > > smartctl -i /dev/sdb; blockdev --getbsz --getpbsz /dev/sdb > Device Model: HGST HUS722T2TALA604 > User Capacity: 2,000,398,934,016 bytes [2.00 TB] > Sector Size: 512 bytes logical/physical > Rotation Rate: 7200 rpm > Form Factor: 3.5 inches > 4096 > 512 > > As you see “–getbsz” forever 4096. I also see logical block size to be 4096 for all devices on my system. > But I think it must be forever 512. > What does it mean? I have seen the following description about logical and physical block sizes somewhere in the internet: "Logical block sizes are the units used by the 'kernel' for read/write operations. Physical block sizes are the units which 'disk controllers' use for read/write operations."
For the problem mentioned in this thread, the physical block size is what you are looking for. > > Thank you. > Ilia. > -- Ingo Franzki eMail: ifran...@linux.ibm.com Tel: ++49 (0)7031-16-4648 Fax: ++49 (0)7031-16-3456 Linux on IBM Z Development, Schoenaicher Str. 220, 71032 Boeblingen, Germany IBM Deutschland Research & Development GmbH / Vorsitzender des Aufsichtsrats: Matthias Hartmann Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294 IBM DATA Privacy Statement: https://www.ibm.com/privacy/us/en/ _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
