Re: grub-install fails when image is 64 meg and succeeds when image is 256 meg

[Andrei Borzenkov]

04.10.2015 13:17, Andrew Stuart пишет:
> This question is also asked here without response: 
> http://unix.stackexchange.com/questions/233748/grub-install-fails-when-image-is-64-meg-and-succeeds-when-image-is-256-meg
>
>
> In the two scenarios below the tst.sh script is exactly the same, except that 
> dd creates a 64 meg image in the first case and a 256 meg image in the second 
> case. (image size is defined by the count argument on the first dd line of the 
> script).
>
> grub installs without error when the image size is 256 meg and fails when the 
> image size is 64 meg.
>
> Any guesses as to why?

Without seeing the actual partition table? No. Please show "fdisk -l" 
for both images.

> First, the version:
>
> (venv3.4)address@hidden:/home/ubuntu/ubuntucore# grub-install -V
> grub-install (GRUB) 2.02~beta2-22ubuntu1.1
>
> SCENARIO 1: GRUB FAILS WHEN dd count=64
>
> (venv3.4)address@hidden:/home/ubuntu/ubuntucore# cat tst.sh
> sudo dd if=/dev/zero of=./test.img oflag=direct bs=1M count=64
> sudo mkdir -p /mnt/build
> sudo parted -s test.img mklabel msdos
> sudo parted -s -a optimal test.img mkpart primary ext2 '0%' '100%'
> sudo parted -s test.img set 1 boot on
> sudo kpartx -av test.img
> sudo mke2fs -L '/' -t ext2 /dev/mapper/loop0p1
> sudo mount /dev/mapper/loop0p1 /mnt/build
> sudo grub-install --root-directory=/mnt/build /dev/loop0
>
> # release mount
> sudo umount -l /mnt/build
> # release loopback
> sudo dmsetup remove loop0p1
> sudo losetup -d /dev/loop0
>
> (venv3.4)address@hidden:/home/ubuntu/ubuntucore# . tst.sh
> 64+0 records in
> 64+0 records out
> 67108864 bytes (67 MB) copied, 0.15139 s, 443 MB/s
> Warning: The resulting partition is not properly aligned for best performance.
> add map loop0p1 (252:2): 0 131071 linear /dev/loop0 1
> mke2fs 1.42.12 (29-Aug-2014)
> Discarding device blocks: done
> Creating filesystem with 65532 1k blocks and 16384 inodes
> Filesystem UUID: 2a52b053-c671-428d-bc13-6b967e0781c5
> Superblock backups stored on blocks:
>      8193, 24577, 40961, 57345
>
> Allocating group tables: done
> Writing inode tables: done
> Writing superblocks and filesystem accounting information: done
>
> Installing for i386-pc platform.
> grub-install: warning: this msdos-style partition label has no post-MBR gap; 
> embedding won't be possible.
> grub-install: warning: Embedding is not possible.  GRUB can only be installed 
> in this setup by using blocklists.  However, blocklists are UNRELIABLE and 
> their use is discouraged..
> grub-install: error: will not proceed with blocklists.
>
> SCENARIO 2: GRUB SUCCEEDS WHEN dd count=256
>
> (venv3.4)address@hidden:/home/ubuntu/ubuntucore# cat tst.sh
> sudo dd if=/dev/zero of=./test.img oflag=direct bs=1M count=256
> sudo mkdir -p /mnt/build
> sudo parted -s test.img mklabel msdos
> sudo parted -s -a optimal test.img mkpart primary ext2 '0%' '100%'
> sudo parted -s test.img set 1 boot on
> sudo kpartx -av test.img
> sudo mke2fs -L '/' -t ext2 /dev/mapper/loop0p1
> sudo mount /dev/mapper/loop0p1 /mnt/build
> sudo grub-install --root-directory=/mnt/build /dev/loop0
>
> # release mount
> sudo umount -l /mnt/build
> # release loopback
> sudo dmsetup remove loop0p1
> sudo losetup -d /dev/loop0
>
> (venv3.4)address@hidden:/home/ubuntu/ubuntucore# . tst.sh
> 256+0 records in
> 256+0 records out
> 268435456 bytes (268 MB) copied, 0.637421 s, 421 MB/s
> add map loop0p1 (252:2): 0 522240 linear /dev/loop0 2048
> mke2fs 1.42.12 (29-Aug-2014)
> Discarding device blocks: done
> Creating filesystem with 261120 1k blocks and 65280 inodes
> Filesystem UUID: 1bf70e68-8f27-426d-b66e-c9c90aaa01b4
> Superblock backups stored on blocks:
>      8193, 24577, 40961, 57345, 73729, 204801, 221185
>
> Allocating group tables: done
> Writing inode tables: done
> Writing superblocks and filesystem accounting information: done
>
> Installing for i386-pc platform.
> Installation finished. No error reported.
>
>
>
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