On Sat, Aug 25, 2018 at 7:40 PM Greg Troxel <g...@lexort.com> wrote: > If the underlying actual disk(s) has 512-byte sectors, so that operations > are the same speed whether aligned or not then it doesn't amtter. > > If the underlying actual disk(s) has 4K sectors (typical on > 2T disks, > and maybe newer disks even if smaller), then you need to set things up > so that actual write operations (that are bigger than 512 bytes) are > lined up so they don't span 4K sectors. > > Filesystems typically have 8K or some other block size, and generally do > 8K (or 4K or 16K) writes, aligned naturally relative to the beginning of > the filesystem. > > But, there's the within-filesystem alignment, and then the fs within the > disklabel, and then the disklabel within the mbr partition. > > All that really matters in the end is that the writes hit the disk > controller aligned. > > So yes, if you use MBR, make the NetBSD partition start at a mulitple of > 64. Then, within disklabel, make every partition start at a multiple of > 64.
Thank you for your reply! Sorry to reply to this so late, but I don't understand why everything should start at a multiple of 64 sectors instead of 8 sectors? Shouldn't it be a multiple of 8 sectors because 8 sectors * 512 bytes/sector = 4096 bytes which aligns with the underlying actual disk's 4K-sized sectors? Lewis