dd is VERY slow for Knoppix - HELP !!!!!

[bruceleung]

Hello,
I am trying to use Knoopix dd to backup a partition to an image file (simulate GHOST.exe to backup my partition). It takes about 2 hours and also exceeds 2GB limit even I use gzip and unix pipe line | . Please see my command as follows :

1) dd if=/dev/hda1 bs=10M | gzip -9 | dd of=/mnt/hda5/drivec.zip bs=10M
{ hda1 is FAT; hda5 is linux ext2 partition }

2) I cannot use mknod (tried to use unix piped line) :
mknod drivec.imp p (it gives an error : Applet NOT found)

Questions : Can anyone help !!!! :
1) How can I improve the method (I used ghost.exe under DOS - it takes only 10min) ?
2) How can I solve the problem for mknod ?
3) /mnt/hda1 is 5GB, but the system occupies 3.5GB ony - how can I use dd or other commands to skip unused data to speed up the backup process ?

Regards,
Bruce

[tom p]

Hi,

guessing in the wild:
* 10M surely isn't an optimal block size for running gzip; try feeding smaller blocks (try 1M or even smaller)
* gzip -9 compresses good but is slow; try running without parameter
* you should also adjust the block size of the output command - your HD surely doesn't use blocks of 10M

On the mknod command: from the error message it doesn't seem to be produced from any mknod program
I know of :-) - what does type mknod say?

On your third remark: you are trying to back up a whole partition including all unused (and ever used) blocks;
you can't expect dd to distinguish between used and unused blocks. And there's also no guarantee that
the unused block contain no data (and thus are compressable to next to nothing). My advice would be to use
a "real" backup program - for the start even "tar" might be appropriate.

Last remark: your output data extension is ".zip"; not that it's important, but more appropriate would be ".gz" -
don't expect any ZIP program to be able to open your backup data file.

Ciao,
Thomas

[Dave_Bechtel]

' man partimage ' ;-)

--Also: try this corrected commandline:
' hdparm -c1 -d1 /dev/hda ' == Turn on DMA and 32-bit

' time dd if=/dev/hda1 bs=10M |gzip -9 > /mnt/hda5/drivec-backup-20050314.gz '

--I dunno what you're trying to do with mknod; that's only for making device(s) manually.


Hello,
I am trying to use Knoopix dd to backup a partition to an image file (simulate GHOST.exe to backup my partition). It takes about 2 hours and also exceeds 2GB limit even I use gzip and unix pipe line | . Please see my command as follows :

1) dd if=/dev/hda1 bs=10M | gzip -9 | dd of=/mnt/hda5/drivec.zip bs=10M
{ hda1 is FAT; hda5 is linux ext2 partition }

2) I cannot use mknod (tried to use unix piped line) :
mknod drivec.imp p (it gives an error : Applet NOT found)

Questions : Can anyone help !!!! :
1) How can I improve the method (I used ghost.exe under DOS - it takes only 10min) ?
2) How can I solve the problem for mknod ?
3) /mnt/hda1 is 5GB, but the system occupies 3.5GB ony - how can I use dd or other commands to skip unused data to speed up the backup process ?

Regards,
Bruce