Re: [gentoo-user] dd says no space left on device

[Mick]

On Sunday 15 May 2011 08:45:05 Adam Carter wrote:
> I'm cloning a windows disk using gentoo;
>
> On the old 66GB disk;
> # dd if=/dev/sdb of=/root/winmbr.bin bs=512 count=1
> # dd if=/dev/sdb1 bs=10M | gzip -v > winpartition.gz
>
> Then after swapping in the new 500GB disk;
> dd if=/root/winmbr.bin of=/dev/sdb bs=512 count=1
> # gunzip -c winpartition.gz | dd of=/dev/sdb1 bs=10M
> dd: writing `/dev/sdb1': No space left on device
> 0+306 records in
> 0+305 records out
> 10137600 bytes (10 MB) copied, 0.109885 s, 92.3 MB/s
> # fdisk -l /dev/sdb
>
> Disk /dev/sdb: 500.1 GB, 500107862016 bytes
> 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
> Units = sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0xe3f7e3f7
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdb1   *      206848   117207039    58500096    7  HPFS/NTFS/exFAT
>
> Why is dd saying no space left after copying 10MB when sdb1 is 65GB?

Not sure if the bs=10M is too large?

You can try finding the optimum size of the bs= value by creating a partition 
on the new disk, formating it and then run something like:

dd if=/dev/zero bs=1024 count=1000000 of=/1G_test.file
dd if=/dev/zero bs=2048 count=500000 of=/1G_test.file
dd if=/dev/zero bs=4096 count=250000 of=/1G_test.file
dd if=/dev/zero bs=8192 count=125000 of=/1G_test.file

and compare the results that dd reports.  bs=4096 often gives best performance 
(on my drives at least) but with the new 1T+ drives you may find that another 
block size does the job better.

Then zero the drive first using dd:

dd if=/dev/zero of=/dev/sdb bs=4096 oflag=direct conv=notrunc

and try repeating your restoring from back up with a more suitable block size.
-- 
Regards,
Mick