At Fri, 12 Mar 2021 14:02:06 -0800, I wrote:
Subject: problems with GPT (and maybe dkctl wedges) on LVM volumes
>
> # gpt -vvv show -a /dev/mapper/rvg0-nbtest.0
> /dev/mapper/rvg0-nbtest.0: mediasize=41943040; sectorsize=512; blocks=81920
> /dev/mapper/rvg0-nbtest.0: PMBR at sector 0
> /dev/mapper/rvg0-nbtest.0: Pri GPT at sector 1
> /dev/mapper/rvg0-nbtest.0: GPT partition: type=ffs, start=64, size=41942943
> gpt: /dev/mapper/rvg0-nbtest.0: map entry doesn't fit media: new start + new size < start + size
> (22 + 13fde < 40 + 27fff9f)
I'm still not quite sure why gpt(8) can't show me the full partition
table when reading from a raw LVM volume (dm) device as above in exactly
the same way it does when reading from the raw (xbd emulated) disk in
the domU.
After all if I map, say, an install.img file, then in the domU I see:
# gpt show -a /dev/rxbd4
start size index contents
0 1 PMBR
1 1 Pri GPT header
2 32 Pri GPT table
34 2014 Unused
2048 262144 1 GPT part - EFI System
Type: efi
TypeID: c12a7328-f81f-11d2-ba4b-00a0c93ec93b
GUID: 97ac9806-df43-4590-ae5b-c88d8861ea0e
Size: 128 M
Label: EFI system
Attributes: None
264192 7544832 2 GPT part - NetBSD FFSv1/FFSv2
Type: ffs
TypeID: 49f48d5a-b10e-11dc-b99b-0019d1879648
GUID: 2865e4e5-a798-4bed-9dc7-2e2317a3d789
Size: 3684 M
Label:
Attributes: biosboot, bootme
7809024 2015 Unused
7811039 32 Sec GPT table
7811071 1 Sec GPT header
and in the dom0 I see the same from the target file:
# gpt show -a /images/NetBSD-9.99.81-amd64-install.img
start size index contents
0 1 PMBR
1 1 Pri GPT header
2 32 Pri GPT table
34 2014 Unused
2048 262144 1 GPT part - EFI System
Type: efi
TypeID: c12a7328-f81f-11d2-ba4b-00a0c93ec93b
GUID: 97ac9806-df43-4590-ae5b-c88d8861ea0e
Size: 128 M
Label: EFI system
Attributes: None
264192 7544832 2 GPT part - NetBSD FFSv1/FFSv2
Type: ffs
TypeID: 49f48d5a-b10e-11dc-b99b-0019d1879648
GUID: 2865e4e5-a798-4bed-9dc7-2e2317a3d789
Size: 3684 M
Label:
Attributes: biosboot, bootme
7809024 2015 Unused
7811039 32 Sec GPT table
7811071 1 Sec GPT header
BTW, I've yet to try ccd(4) as an interpolative layer to add
"paritionable disk" semantics -- my first attempt on the older
(production) Xen system where I was testing this on resulted in a hard
crash as I was running "ccdconfig -u ccd0" to try a different LVM. I
need to run through the exercise of letting sysinst partition up an xbd0
to try this again on a newer, and less critical, Xen server.
--
Greg A. Woods <gwoods%acm.org@localhost>
Kelowna, BC +1 250 762-7675 RoboHack <woods%robohack.ca@localhost>
Planix, Inc. <woods%planix.com@localhost> Avoncote Farms <woods%avoncote.ca@localhost>
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