Re: [opensuse] Corrupted harddisk, recovery??
- From: Chuck Payne <terrorpup@xxxxxxxxx>
- Date: Tue, 1 Sep 2009 18:07:21 -0400
On Tue, Sep 1, 2009 at 4:42 PM, John Andersen<jsamyth@xxxxxxxxx> wrote:
� wrote:
On 01/09/09 16:26, Anders Johansson wrote:
On Tuesday 01 September 2009 22:17:43 Bruce Samhaber wrote:
The drive with problems has Windows 98 installed on it, formatted as NTFS.Really? I didn't think win98 supported NTFS
It doesnt. Only in NT-based versions ,since 3.1.
http://www.softlookup.com/display.asp?id=25391
NTFS for Windows 98 v1.03 Description:
NTFS file system driver which allows you to access any NTFS drives present on your system. Once you install the program, any NTFS (New
Technology File System) drives present on your system become fully accessible as native Windows 98 volumes.
NTFS for Windows 98 takes a unique approach to providing cross-platform file system support. Rather than implement code to read and write
NTFS drives, the program uses the NTFS and NTOSKRNL system files from a Windows NT or Windows 2000 configuration.
It wraps the Windows NT/2000 NTFS driver in a run-time environment that simulates the Windows NT environment the NTFS driver is written to use.
Thus, NTFS for Windows 98 does not rely on potentially unreliable reverse-engineered information about NTFS, provides ultimate compatibility
with NTFS, and takes advantage of Microsoft NTFS bug fixes whenever you update the NTFS driver file it uses to a more recent version.
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This does great for linux. It takes a while to work. Not sure if this
what you want but take a look. It was at this link but the author
taken it down, I made a copy for my notes because it was so helpful.
-------------------------------------
Everyone gets bad sectors eventually (unless you are lucky/spoiled
enough to get a new PC every year); they are noted by the tell-tale
error messages:
Buffer I/O error on device sdc2, logical block 173539331
ata4: translated ATA stat/err 0x51/40 to SCSI SK/ASC/ASCQ 0x3/11/04
ata4: status=0x51 { DriveReady SeekComplete Error }
ata4: error=0x40 { UncorrectableError }
That is, of course if you are running a normal OS like *nix, good luck
figuring out what the hell is going on when this happens in Windows.
Probably some kind of generic “Input/Output error” messages will be
flying about, if you even get a bootable system.
Regardless of what you were running go out and get yourself a copy of
RIP (Recovery-is-possible Bootable Linux Rescue CD). Most of the
operations you are about to perform require the drives to be in an
unmounted (offline) state, so doing this from a running system may be
impossible and is definitely not recommended.
Most of the guides I have seen out there get right into zeroing
blocks, and for many users it may seem daunting without first
understanding some basics about hard drive operation.
First off you should be sure you are actually dealing with bad
sectors, and not something on the filesystem level such as simple
corruption. When something occurs at the filesystem level (software),
sometimes the system misplaces or corrupts individual files and this
is easily fixable using a filesystem scan/fix program such as
(scandisk, fsck) and it will either be able to piece the files back
together or not (probably not). However when true bad sectors occur at
the hardware level (above-mentioned errors and sometimes repetitive
clicking sounds from the actual drive), the fix involves manipulating
the actual blocks on the drive, regardless of the filesystems and
partitions present.
Statistically speaking, once a drive develops bad blocks/sectors the
likelihood of more occurring is greatly increased. With today’s drive
prices its not worth using the drive any longer, conduct the fix to
get the filesystem mountable again and get whatever data you can onto
a new drive. 99% of modern drives contain a feature set called
S.M.A.R.T which includes many low-level scanning and maintenance
tools. Moreover, these drives are not stupid, when an attempt to write
to a bad block is made, the drive automatically adds that block to a
list and never attempts to use it again. Note that I highlighted the
term write, since regular scanning programs find bad sectors by
reading them; this will not force reallocation. They will not attempt
writes since they do not want to destroy the data contained in the
block (albeit small, usually 1-4kB depending on the filesystem’s block
size, unless the block is contained with the free space portion) which
is pretty much useless anyway. Very rarely a bad block will suddenly
start functioning after 3-5 read attempts.
So the procedure in a nutshell: Find the bad blocks, force
reallocation by writing zeros to the block address, repair the
filesystem, backup.
Find the bad blocks:
S.M.A.R.T has what is called an “Extended Offline Test” which goes
block-by-block attempting to read until it finds a failure, then
aborts. This test runs in the background and after a certain time you
can view the results. This will let you know the first block which is
unreadable, if you suspect there being many blocks it is then prudent
to run an additional script to check the surrounding blocks, or simply
re-run the smartctl test.
# smartctl -t long -d ata /dev/sdc
# smartctl -l selftest -d ata /dev/sdc
smartctl version 5.36 [i686-pc-linux-gnu] Copyright (C) 2002-6 Bruce Allen
Home page is http://smartmontools.sourceforge.net/
=== START OF READ SMART DATA SECTION ===
SMART Self-test log structure revision number 1
Num Test_Description Status Remaining
LifeTime(hours) LBA_of_first_error
1 Extended offline Completed: read failure 40% 16786
2037331
The Logical Block Address (LBA) of the first error is given, however
to be able to do anything with it we must translate it to the actual
address of the block as seen by the filesystem. Depending on the
filesystem in question you must either find out or know the block size
being used, here are some examples (if you are not sure use an
appropriate tool for your filesystem and find out):
FAT32 (default): 512 bytes
NTFS (default): 512 bytes
ext3 (default): 512 bytes
reiserfs (default): 4096 bytes
In this example (since I was repairing a reiserfs system) I am using
4096 bytes as the block (or sometimes known as sector in Windows)
size. Take a look at your partition layout to determine where the
block lies.
# fdisk -ul
...
Disk /dev/sdc: 122.9 GB, 122942324736 bytes
255 heads, 63 sectors/track, 14946 cylinders, total 240121728 sectors
Units = sectors of 1 * 512 = 512 bytes
Device Boot Start End Blocks Id System
/dev/sdc1 63 2008124 1004031 82 Linux swap / Solaris
/dev/sdc2 2008125 240107489 119049682+ 83 Linux
I have truncated the above output, but you can see that the LBA#
2037331 lies in the second partition of the third drive /dev/sdc2. In
the case of reiserfs or any non-512 byte block size, a simple
calculation is necessary to get the filesystem’s address of the block.
# echo "(2037331-2008125)*512/4096" | bc -l
3650.75000000000000000000
3650 is our block (notice the damage is actually near the last 1/4 of it)!
Zero the block:
# dd if=/dev/zero of=/dev/sdc2 bs=4096 count=1 seek=3650
1+0 records in
1+0 records out
4096 bytes (4.1 kB) copied, 0.000255 seconds, 16.1 MB/s
If the speed noted about is something like 1000MB/s+ then it’s likely
that your command has something wrong.
Re-scan
The reason I rescan the entire disk is to make sure no new bad blocks
are developing in the previously confirmed area (if they are, your
chances of repair just dropped dramatically).
# smartctl -t long -d ata /dev/sdc
If your long scan completes without error, that’s it! Run the
appropriate filesystem repair utility and reboot. If not, repeat.
Alternative
If you are realizing the number of bad blocks increasing or there
simply being large areas of damage a complete duplicate of the
partition/drive may be in order. A program called dd_rescue is ideal
for this as it will copy the entire area block-by-block and write out
zeros automatically for bad blocks at your destination.
Most people in this case will not have the free space available
locally to duplicate an entire drive. Either go out and buy a new
drive, or mount some space on another machine over ssh/smb.
# sshfs username@xxxxxxxxxxx:/home/username /mnt/hd
Usage: smbmnt mount-point [options]
Use dd_rescue to copy the entire drive to a file, or directly to
another drive mounted locally.
# dd_rescue -A -v -b 4096 /dev/sdc2 /mnt/hd/badblocks.img
Always set -B to the filesystem block size. When the copy operation
completes successfully you will have an idea of how much data was
lost, and then run the filesystem repair utility on that to rebuild.
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- References:
- [opensuse] Corrupted harddisk, recovery??
- From: Bruce Samhaber
- Re: [opensuse] Corrupted harddisk, recovery??
- From: Anders Johansson
- Re: [opensuse] Corrupted harddisk, recovery??
- From: Cristian Rodríguez
- Re: [opensuse] Corrupted harddisk, recovery??
- From: John Andersen
- [opensuse] Corrupted harddisk, recovery??
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