Re: dd hung up by disk errors
On Jul 20, 2009, at 22:26 , Siggy Brentrup wrote: I'm willing to accept some sectors as lost, but it would really help if there were a way to do so quickly. Is there? I'd skip to about 63G (dont forget to seek), yielding a hole in your image using noerror. As soon as you have saved the bulk of your data, you may try to fill the holes using count to not overwrite stuff you You might want to look for dd_rhelp, a script around dd_rescue that automates that process. A. -- Ansgar Esztermann DV-Systemadministration Max-Planck-Institut für biophysikalische Chemie, Abteilung 105 -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: dd hung up by disk errors
On Mon, Jul 20, 2009 at 09:43:13AM -0700, Ross Boylan wrote: I have a bad drive in a laptop and am attempting to salvage what I can with (roughly) dd conv=noerror,sync if=/dev/sda3 of=/nfs/backup where the of is NFS mounted from another system. This keeps trying when it encounters a disk read error, but there are lots of errors and it is very slow (only 200MB transferred in c 9 hours). The first 62G went OK, but the disk is c 75G. I'm willing to accept some sectors as lost, but it would really help if there were a way to do so quickly. Is there? I think the drive is SATA; it's in a Dell Latitude D630 laptop. I booted off a Knoppix 5.1 CD. sda3 is an NTFS partition. As others has noted, use of dd with seek etc. will do most. I have made list of data recovery tools on Debian. http://www.debian.org/doc/manuals/debian-reference/ch10.en.html#_data_file_recovery_and_forensic_analysis This may help later. Anyway, your harddisk may be faulty. It sounds like to get new one. If I were you and I have minimum budget and hardware (I mean no extra PC), I will go buy new SATA disk and external SATA/USB kit. 1. Buy 500GB SATA at below $100 (160GB below $50) This should be enough space. 2. Do fresh install. (Both NT/XT and Debian) 3. Put old disk on USB box and work on data recovery. Osamu -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: dd hung up by disk errors
On Tue, 2009-07-21 at 23:27 +0900, Osamu Aoki wrote: On Mon, Jul 20, 2009 at 09:43:13AM -0700, Ross Boylan wrote: I have a bad drive in a laptop and am attempting to salvage what I can with (roughly) dd conv=noerror,sync if=/dev/sda3 of=/nfs/backup where the of is NFS mounted from another system. This keeps trying when it encounters a disk read error, but there are lots of errors and it is very slow (only 200MB transferred in c 9 hours). The first 62G went OK, but the disk is c 75G. I'm willing to accept some sectors as lost, but it would really help if there were a way to do so quickly. Is there? I think the drive is SATA; it's in a Dell Latitude D630 laptop. I booted off a Knoppix 5.1 CD. sda3 is an NTFS partition. As others has noted, use of dd with seek etc. will do most. I have made list of data recovery tools on Debian. http://www.debian.org/doc/manuals/debian-reference/ch10.en.html#_data_file_recovery_and_forensic_analysis This may help later. Thank you very much for making that available, and thanks to the other posters for their suggestions. Anyway, your harddisk may be faulty. It sounds like to get new one. The drive reports it has already failed. I have a new one, but am trying to salvage what I can. I haven't tried to transfer the bad drive to a new enclosure because I anticipate it will fail completely soon. If I were you and I have minimum budget and hardware (I mean no extra PC), I will go buy new SATA disk and external SATA/USB kit. I have a newer, bigger laptop disks and am backing up to my main hard drive. Some tidbits: Initially I transferred using something like dd conv=noerror,sync if=/dev/sda3 | ssh bigcomputer cat sda3.image I didn't realize that stdin could be directed across the network like this. However, this imposes the overhead of ssh. I had /usr/local/backup/cotton 192.168.40.0/24(insecure,sync,rw,no_subtree_check,all_squash,anonuid=1000) in /etc/exports, but my initial attempts to mount failed with some error talking about bad superblock. The fix was to mount with -o nolock. Also, I tried piping through bzip: dd conv=noerror,sync if=/dev/sda3 | bzip2 | ssh However, this gave me lower throughput (in terms of bytes of the original file). And for some reason, the compression was pretty effective on my other partitions (e.g., 10% of original size) but quite ineffective with the Vista file system (about 2/3 of original size). The Vista partition is relatively full of real data (much of it my daughter's music files, which I guess are already compressed), but still this was a little surprising. The partition is not encrypted. All the other partitions seem to read without error. Finally, I think my choice of block size was suboptimal. I got at best 20MB/s on Gigabit ethernet, on which I would hope for around 100MB/s. With bzip2 the compression was clearly the limiting factor. I suspect a larger write block size, and maybe a larger read block size, would have helped. I did some earlier backup to a SAMBA share; that method too had pretty dismal throughput, even given that was on 100Mb ethernet. Some of the rescue programs say they try big blocks first and then back down to smaller ones if there is an error, in hopes of getting the most sectors possible. I suppose one advantage of larger input block sizes is that they reduce the number of attempted reads, and so get you through the bad spots faster--at the cost of possibly missing some readable sectors. Ross 1. Buy 500GB SATA at below $100 (160GB below $50) laptop disks are a little pricier. This should be enough space. 2. Do fresh install. (Both NT/XT and Debian) 3. Put old disk on USB box and work on data recovery. Osamu -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
dd hung up by disk errors
I have a bad drive in a laptop and am attempting to salvage what I can with (roughly) dd conv=noerror,sync if=/dev/sda3 of=/nfs/backup where the of is NFS mounted from another system. This keeps trying when it encounters a disk read error, but there are lots of errors and it is very slow (only 200MB transferred in c 9 hours). The first 62G went OK, but the disk is c 75G. I'm willing to accept some sectors as lost, but it would really help if there were a way to do so quickly. Is there? I think the drive is SATA; it's in a Dell Latitude D630 laptop. I booted off a Knoppix 5.1 CD. sda3 is an NTFS partition. Thanks. Ross Boylan -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: dd hung up by disk errors
i have never used any of them, but I think ddrescue, gddrescue and myrescue (apt packages) are made for what you're doing. good luck, Tiago Saboga. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Re: dd hung up by disk errors
On 2009-07-20 at 09:43 -0700, Ross Boylan wrote: I have a bad drive in a laptop and am attempting to salvage what I can with (roughly) dd conv=noerror,sync if=/dev/sda3 of=/nfs/backup where the of is NFS mounted from another system. This keeps trying when it encounters a disk read error, but there are lots of errors and it is very slow (only 200MB transferred in c 9 hours). The first 62G went OK, but the disk is c 75G. man dd, in particular ibs, obs, skip, seek and options noerror and notrunc. I'm willing to accept some sectors as lost, but it would really help if there were a way to do so quickly. Is there? I'd skip to about 63G (dont forget to seek), yielding a hole in your image using noerror. As soon as you have saved the bulk of your data, you may try to fill the holes using count to not overwrite stuff you already saved. Sorry, all this is from the top of my head, for the exact syntax I'd better look at the manpage too. I think the drive is SATA; it's in a Dell Latitude D630 laptop. I booted off a Knoppix 5.1 CD. sda3 is an NTFS partition. Irrelevant in this context. Happy loop mounting Siggy -- Please don't Cc: me when replying, I won't see either :P bsb-at-psycho-dot-informationsanarchistik-dot-de or:bsb-at-psycho-dot-i21k-dot-de O ascii ribbon campaign - stop html mail - www.asciiribbon.org signature.asc Description: Digital signature
Re: dd hung up by disk errors
If your bad sectors are local to a particular area of the disk, you could read sections starting at the end, and moving towards the beginning after each section is completed. Later you would concatenate the sections that were recoverable. Give either iseek=n or skip=n to dd to skip over a portion of the disk. Also download, burn and boot off the SystemRescueCd - it has a lot of tools for this sort of thing: http://www.sysresccd.org/Main_Page Don Quixote -- Don Quixote de la Mancha quix...@dulcineatech.com http://www.dulcineatech.com Dulcinea Technologies: Software of Elegance and Beauty. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
