Hi: PROBLEM I came across a very weird situation because HDD-manufacturer counts HDD space according to metric system instead of multiplication of 1024 (2^10). This mismatches the space capacity between what OS filesystems calculate HDD space. Secondly, each HDD manufacturer has different total byte size for what they claim as the same sized HDDs. With the above two scenarios, it poses a nuisance to replace a corrupted HDD with another HDD from another manufacturer even though they claim that they are of the equal size, but differs by a few bytes. Thus, zfs does not accept the new HDD. SOLUTION A way around is to create a sparse zfs dataset at the beginning, according to the HDD-manufacturer defined metric system of HDD space measurement at the power of 10 rather than 2^10. BUT ANOTHER PROBLEM However, I came across another odd situation with the bsdinstaller with FreeBSD 10-Beta2 which has an option to install root in zfs. The bsdinstaller script is flawless as it is. But it does not address the disksize mismatch problem as stated above. Any workaround will be appreciated! It would be a nice feature if the new bsdinstaller in FreeBSD10 allows the user first to make a sparse zfs dataset before installing root in zfs. Thanks! /z
On Nov 3, 2013 1:07 AM, "Zenny" <garbytrash at gmail.com> wrote:> > Hi: > > PROBLEM > > I came across a very weird situation because HDD-manufacturer counts > HDD space according to metric system instead of multiplication of 1024 > (2^10). This mismatches the space capacity between what OS filesystems > calculate HDD space. > > Secondly, each HDD manufacturer has different total byte size for what > they claim as the same sized HDDs. > > With the above two scenarios, it poses a nuisance to replace a > corrupted HDD with another HDD from another manufacturer even though > they claim that they are of the equal size, but differs by a few > bytes. Thus, zfs does not accept the new HDD. > > SOLUTION > > A way around is to create a sparse zfs dataset at the beginning, > according to the HDD-manufacturer defined metric system of HDD space > measurement at the power of 10 rather than 2^10. > > BUT ANOTHER PROBLEM > However, I came across another odd situation with the bsdinstaller > with FreeBSD 10-Beta2 which has an option to install root in zfs. The > bsdinstaller script is flawless as it is. But it does not address the > disksize mismatch problem as stated above. Any workaround will be > appreciated! > > It would be a nice feature if the new bsdinstaller in FreeBSD10 allows > the user first to make a sparse zfs dataset before installing root in > zfs. Thanks!The workaround is simple: create a partition that starts at 1 MB and leaves 1 MB free at the end of the disk. However, that workaround is no longer needed, as ZFS v22-ish introduced a similar workaround internally. So it's possible to use while disks that differ in size by 1MB or two without any issue.
On Nov 3, 2013, at 1:07 AM, Zenny <garbytrash at gmail.com> wrote:> Hi: > > PROBLEM > > I came across a very weird situation because HDD-manufacturer counts > HDD space according to metric system instead of multiplication of 1024That is not weird or unusual. For example, 72GB disks range from 72GB to 73.1GB (or so) in size. It doesn't really have anything to do with the 1024 vs 1000 measurement issue. Manufacturing variations result in a lot of different sizes. Major commercial storage vendors automatically round down to the nearest known increment. This worked well for SCSI disks, as they always doubled in size each generation (9, 18, 36, 72, 144, etc.). It doesn't work as well with SATA disks. Or down to the nearest whole GB, if it is not a known size. Tom