Date: Sat, 27 Dec 2003 08:16:04 -0800 From: "Drew Tomlinson" <drew@mykitchentable.net> To: "FreeBSD Questions" <freebsd-questions@freebsd.org> Subject: Can I Boot From ad1? How? Message-ID: <00a901c3cc94$ba5080d0$0301a8c0@bigdaddy>
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I have a 4.9 system that has two identical 850 MB drives and a 4 GB drive. The system boots from one of the 850 MB drives (ad0s1a) and uses a 50 MB slice (?) for root. The rest of this drive is unused. The 4 GB drive (ad2s1e) contains /usr. The other standard filesystems such at /var, /tmp, etc. are symlinked to /usr/* as suggested in The Complete FreeBSD for simple systems. Anyway, the system is sometimes inaccessible due to a flurry of hard errors on ad0. The only way into the system is to power off/on and then let fsck sort things out. Then the system will run fine for days and even weeks but it will eventually happen again. I suspect a complete disk failure is eminent. Thus, I would like to use ad1 (the unused 850 MB drive) in place of ad0 but instead of limiting the root partition to 50 MB, I'd like to just use the whole disk. I have followed instructions from man and web pages in an attempt to get this going. I used /stand/sysinstall to fdisk and added the boot flag. Here's the current fdisk output: blacksheep# fdisk -s ad1 /dev/ad1: 6616 cyl 4 hd 63 sec Part Start Size Type Flags 1: 0 1667232 0xa5 0x80 Then I used /stand/sysinstall to disklabel and newfs. Here's the current disklabel output: blacksheep# disklabel ad1 # /dev/ad1c: type: ESDI disk: ad1s1 label: flags: bytes/sector: 512 sectors/track: 63 tracks/cylinder: 4 sectors/cylinder: 252 cylinders: 6616 sectors/unit: 1667232 rpm: 3600 interleave: 1 trackskew: 0 cylinderskew: 0 headswitch: 0 # milliseconds track-to-track seek: 0 # milliseconds drivedata: 0 8 partitions: # size offset fstype [fsize bsize bps/cpg] a: 1667232 0 4.2BSD 2048 16384 90 # (Cyl. 0 - 6615) c: 1667232 0 unused 0 0 # (Cyl. 0 - 6615) Next, I mounted ad1s1a and used the dump/restore example from the FAQ to copy the contents of ad0s1a to ad1s1a. Now for the test... I read the boot man page and surmised that the way to boot from ad1 was to use '1:ad(0,a)/kernel' at the boot prompt but I get this error: Disk error 0x1 (lba=0x47a14bc0) Invalid format I've never attempted anything like this before so it's very possible I'm missing something basic. Any ideas? Thanks, Drew
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