sanboot and bootsector
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2013-10-13, 11:20
(This post was last modified: 2013-10-13 11:36 by erwan.l.)
Post: #1
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sanboot and bootsector
Hi There,
I have no pb sanbooting a disk image file with a partition boot sector offset = 63 sectors (32256 bytes). Command is : sanboot --drive 0x80 ${boot-url}/_images/xp.img . However, when partition offset is 2048 (1048576 bytes), it wont boot. (sanboot error 1d0c6139). That same image boots fine via other means (iscsi, aoe, boot from disk, etc) so I know the image is fine. Moreover, when sniffing packets, I notice than ipxe/sanboot first pushes a HTTP HEAD request at 32768 bytes (=64 sectors). I have the feeling that this is a mistake. Immediately after, I see another HTTP HEAD at 0 bytes, which I guess is to read the MBR. And finally right after, I see a HTTP HEAD at 32256 bytes (my partition offset) and then the boot start. So I have 2 questions : -is not there a mistake in sanboot+http since first HTTP HEAD goes to 32768? I would recommend to look by default at 32256. -is it possible to boot disk images with a partition offset at 1048576 (default with latest windows versions) ? Note that at this stage, the content of my disk image is not relevant. It is a plain disk image file with a MBR and one partition with a BS. Thanks ! Erwan Erwan L. - website : http://erwan.labalec.fr blog : http://labalec.fr/erwan/ |
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2013-10-14, 15:15
(This post was last modified: 2013-10-15 13:14 by robinsmidsrod.)
Post: #2
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RE: sanboot and bootsector
(2013-10-13 11:20)erwan.l Wrote: -is not there a mistake in sanboot+http since first HTTP HEAD goes to 32768? This isn't a mistake. The code in int13.c will look at offset 32768 for an ISO9660 primary volume descriptor, to find out if the SAN-booted device is a CD-ROM image. The fact that you see a read from offset 32256 indicates that the MBR code is executing correctly and attempting to read from the correct partition offset. Quote:-is it possible to boot disk images with a partition offset at 1048576 (default with latest windows versions) ? Yes, there should be no problem with that. The error you are experiencing (http://ipxe.org/1d0c6139) indicates that your web server is returning some kind of error status code which iPXE doesn't know how to handle. Could you check your web server logs (or enable DEBUG=httpcore) to find out what status is being returned? Michael |
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2013-10-14, 15:23
Post: #3
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RE: sanboot and bootsector
Ok got it !
So it first checks offset 32768 for an iso volume descriptor, if not found goes back to offset 0 to read the mbr and from there gathers what ever offset it needs to jump to (usually 32256 or 1048576 for latest windows disks). I was wondering where the code was : will look at int13.c with interest ! I'll check my web server to check the error codes. Thanks for your support ! Erwan L. - website : http://erwan.labalec.fr blog : http://labalec.fr/erwan/ |
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