On Sun, Jul 14, 2013 at 02:07:41PM +1000, Tim Connors wrote: > Other than the compatibility reason stated there, this FAQ, and the > differing behaviour of the scheduling elevator dependent upon whether > it's a disk or a partition, has always *smelt* to me.
it's not about whether it's a disk or a partition, it's about the alignment of the partition with a multiple of the sector size. 4K alignment works for both 512-byte sector drives and 4K or "advanced format" drives > If dealing with a whole disk, it still creates -part1 & -part9 anyway. yep, it creates a GPT partition table so that the data partiton is 4K-aligned. interesting discussion here: https://github.com/zfsonlinux/zfs/issues/94 in theory, zfs could use the raw disk and start at sector 0, but one of the risks there is that careless use of tools like grub-install (or fdisk/gdisk/parted etc) could bugger up your pool....and there's really no good reason not to use a partition table, at worst you lose the first 1MB (2048 x 512 bytes) of each disk. > eh? parted has done proper alignment by default since just after the > dinosaurs were wiped out. it's still quite common for drives to be partitioned so that the first partition starts on sector 63 rather than 2048 - which works fine for 512-byte sectors but not so great for 4K-sector drives. and i know i've spent significant amounts of time in the past, tediously calculating the optimum offsets for partitions to use with mdadm. craig -- craig sanders <[email protected]> BOFH excuse #424: operation failed because: there is no message for this error (#1014) _______________________________________________ luv-main mailing list [email protected] http://lists.luv.asn.au/listinfo/luv-main
