Re: bsdinstall misaligns partitions
Christian Weisgerber wrote: Shouldn't bsdinstall attempt to align partitions on 4k boundaries both for the benefit of 4k drives and flash storage? 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. * Funnily enough, the ancient BSD dangerously dedicated scheme is the only one that out of the box does not misalign partitions. I'm presumably not the first one to notice this issue, and yes, I'm mostly just venting. Best advice is go submit a pr on this bsdinstall situation. ___ 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
bsdinstall misaligns partitions
Shouldn't bsdinstall attempt to align partitions on 4k boundaries both for the benefit of 4k drives and flash storage? 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. * Funnily enough, the ancient BSD dangerously dedicated scheme is the only one that out of the box does not misalign partitions. I'm presumably not the first one to notice this issue, and yes, I'm mostly just venting. -- Christian naddy Weisgerber na...@mips.inka.de ___ 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
Re: bsdinstall misaligns partitions
On Fri, Jan 4, 2013 at 9:14 AM, Christian Weisgerber na...@mips.inka.dewrote: Shouldn't bsdinstall attempt to align partitions on 4k boundaries both for the benefit of 4k drives and flash storage? That's rather up to you. AFAIK it attempts to create partitions that preserve cylinder boundaries - which are generally a rather obsolete concept, even for drives with spindles. ___ 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
Re: bsdinstall misaligns partitions
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
Re: bsdinstall misaligns partitions
Warren Block: * 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. Yes and no. If you look at the bsdlabel(8) output, the size of 'c' is exactly the same as the sum of the sizes of the other partitions, as well as exactly the size of the fdisk slice. There is no additional reserved space for the label. So where does the disklabel hide? FFS1 (FFS2) leaves 8 kB (64 kB) of space at the start of _every_ filesystem. The first 8 kB of the slice--overlapping with the start of 'c' and the start of 'a'--hold boot1, the disklabel, and boot2. If you hexdump /boot/boot2, you'll notice that the first 0x114 bytes are zeroed out; those 276 bytes are exactly where the disklabel is located on disk. See sys/disklabel.h and ufs/ffs/fs.h. -- Christian naddy Weisgerber na...@mips.inka.de ___ 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
