On Fri, 4 Jan 2013, Christian Weisgerber wrote:
Shouldn't bsdinstall attempt to align partitions on 4k boundaries both for the benefit of 4k drives and flash storage?
I think the latest version does.
I just installed 9.1R i386 for fun and practice, in fact I installed it several times, and I played around with the partitioning options. * The modern GPT scheme reserves 34 sectors at the start of the disk. Your newly created partitions will start at offset 34 and will therefor be misaligned. I ended up configuring a 63 kB freebsd-boot partition, which ensures that the following partitions are aligned. * The old MBR scheme is even worse. The FreeBSD slice will start at sector 63, guaranteeing that any partitions contained within will be misaligned. There is no way to fix this, unless you shell out and run fdisk manually.
Even worse news: you can't fix it manually. Both fdisk and gpart are slaves to the kernel code that deals with MBR layouts, and will align to the old CHS values. I have not found a way to use FreeBSD to create an MBR slice that starts at 1M, block 2048. The CHS alignment always forces it to block 2079, a multiple of 63.
However, gpart's -a alignment flag will offset BSD partitions within the slice so they are aligned.
* Funnily enough, the ancient BSD "dangerously dedicated" scheme is the only one that out of the box does not misalign partitions.
The filesystems don't begin at the start of the slice anyway. There is a bsdlabel there.
I'm presumably not the first one to notice this issue, and yes, I'm mostly just venting.
A way to override the CHS alignment would be welcome. _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
