Messages in this thread | | | Date | Tue, 12 Feb 2008 16:04:52 +0100 (CET) | From | Jan Engelhardt <> | Subject | Re: BTRFS partition usage... |
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> On Feb 12 2008 09:35, Chris Mason wrote: >> >> and slap the bootloader into "MBR", just like on x86. >> Or I am missing something.. > >It was a request from hpa, and he clearly had something in mind. He kindly >offered to review the disk format for bootloaders and other lower level >issues but I asked him to wait until I firm it up a bit. > >From my point of view, 0 is a bad idea because it is very likely to conflict >with other things. There are lots of things in the FS that need deep >thought,and the perfect system to fully use the first 64k of a 1TB filesystem >isn't quite at the top of my list right now ;) > >Regardless of offset, it is a good idea to mop up previous filesystems where >possible, and a very good idea to align things on some sector boundary. Even >going 1MB in wouldn't be a horrible idea to align with erasure blocks on SSD.
I still don't like the idea of btrfs trying to be smarter than a user who can partition up his system according to (a) his likes (b) system or hardware requirements or recommendations to align the superblock to a specific location.
1MB alignment does not always mean 1MB alignment. Sector 1 begins at 0x7e00 on x86. And with the maximum CHS geometry (255/63), partitions begin at 0x7e00+n*8225280 bytes, so the SB is unlikely to ever be on a 1048576 boundary.
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