Filesystem issue

Started by winfried, September 21, 2006, 10:32:27 am

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Hi there,

I'd like to know, if there is a method, to mark a sector in a filesystem as "bad".
My scsi disk has a couple of bad sectors, which can't me remapped within the disk (i tried it with the bios function "verify disk" in my adaptec controller, but the sectors can't be remapped).
Now, I'd like to avoid the filesystem to use those sectors. Btw., "reasb" doesn't work, it tries to remap the sector in the scsi drive, which will fail in my case (tried it and got the filesystem totally messed up).
Is there a method, to accomplish this task? In some unix systems, there used to be a filesystem debugger (fsdb), which could have been used for this, but no such thing in NS  :cry:


You sound like your running on a PC?, usually to map out bad blocks on a SCSI disk on a PC requires a low level format, some hard disk manufacturers have utils that generally run under DOS that will perform a low level format (takes ages on large disks) and map out bad blocks and sectors.  I don't think you're going to get anything to fix it under the NeXT file system with the system live.  I think it will require a low level format.  From memory I think low level formats may on some disks be actually carried out by the drives firmware.  I've had the most success on my low level formats using my Macintosh 840av.  I did a Quantum Atlas 10K2 recently and it took all day.

SCSI disks are a headache, finding ones that work on a NeXT even more so, Seagate are the best bet.  IBM are a pain in the a**.

Is it not a sign of impending doom that the disk has done this and needs to be replaced, from my experience (pretty poor of scsi disks in general, as I've killed quite a few), when they start to mess up they generally die not long afterwards.
NeXTcube Turbo Dimension, NeXTstation Turbo Color, MP2100, Q840av, Q650, WS G4 500, Pismo G4 550, SGI Octane R12K MXE, BeBox 133.


Yes, it's an intel system.
I'm not sure, if a low level format will help, cause I assume, that similar functions are used as in the verify function (which is low level, cause executed from the scsi controllers bios), and this didn't work (the verify procedure tried to remapp the bad sectors but failed on two specific sectors, where the scsi controller printed an error message).
I was also hoping to avoid a format cause it's on the root partition of my system and I don't want to reinstall the system.

To mark a specific sector in the filesystem as used, should be an easy task to do, if a tool would be available to access the ufs filesystem structures. Maybe, I'll create something on my own.
With the filesystem debuggers, mentioned above, it would be easy to do this, cause it provides methods to access those internal structures (traverse through file system blocks, check which blocks are connected to an inode, access the superblocks etc.).