XPost: alt.comp.os.windows-10   
   From: noreply@ghyhgtgfrde.com   
      
   On 25/01/2025 15:55, Alan K. wrote:   
   > On 1/25/25 10:36 AM, Paul wrote:   
   >> I was experimenting with a hard drive the other day,   
   >> a 4TB one, and making the C: drive really large.   
   >> This was to counter a complaint from some software   
   >> "insufficient space to..." type error.   
   >>   
   >> So anyway, I could see a green stripe of material about   
   >> half way out on the disk. I figured, no problem,   
   >> if I want to shrink the disk, that material will move   
   >> out of the way for me.   
   >>   
   >> It didn't.   
   >>   
   >> I got an error, that said the material could not be moved,   
   >> and it was different than the usual material problem. It was   
   >> traceable to $BADCLUS, a cluster marked off by the file   
   >> system driver. Apparently, the SMART log reported a   
   >> series of "UDMA CRC errors". These are errors on the   
   >> packets on the SATA cable, causing the packets to be   
   >> retransmitted. That's not a conventional data CRC as such.   
   >> Yet, the software decided that this constituted a bad cluster,   
   >> so the area on the disk was marked off.   
   >>   
   >> There is a option in CHKDSK, to verify bad clusters, but this   
   >> in fact, scans the entire partition again, as if doing a /r .   
   >>   
   >> This would check for errors, and bad clusters.   
   >>   
   >>     chkdsk /f /r  C:     # Fix structural errors, read-scan all   
   >> clusters to verify they are working   
   >>                          # Mark off new bad   
   clusters. Do not verify   
   >> any existing bad clusters.   
   >>   
   >>     chkdsk /b     C:     # This seemingly does the same thing,   
   but can   
   >> turn bad clusters into good clusters.   
   >>                          # If a cluster was   
   "flagged by mistake", this   
   >> can undo it.   
   >>   
   >> On a large disk, this can take hours to complete (either command).   
   >>   
   >> When the /b run completed, it reported   
   >>   
   >>     "Removing 1 clusters from the Bad Clusters File."   
   >>   
   >> and that is what I was hoping would happen on the /b run.   
   >>   
   >> I went back to Disk Management, and I still could not shrink the volume.   
   >> It was still reporting there was a problem with the same issue as   
   >> previously.   
   >>   
   >> On a hunch, I booted a Windows 7 disk, cabled up the affected drive,   
   >> and did a regular CHKDSK on the partition in question. I know at this   
   >> point, there is nothing wrong with any clusters, so there is no need to   
   >> do an hours-long scan yet again.   
   >>   
   >>     chkdsk /f K:         # Windows 7 CHKDSK (of the second disk   
   drive   
   >> affected partition)   
   >>   
   >> and finally, after this, the Shrink menu started working again in   
   >> Disk Management. Presumably this is related to Windows 7   
   >> correcting $BITMAP-type issues. (W10/W11 don't handle $BITMAP   
   >> properly on partitions any more, leaving data at rest in an   
   >> indeterminate state.) Windows 7 cares about the $BITMAP, and   
   >> fixed it up for me.   
   >>   
   >> Disk is now back to normal again. The shrink completed (2TB partition   
   >> down   
   >> to 200GB) with no trouble at all. When a partition starts small, you make   
   >> it huge, then there won't be a problem to make it as small as it was   
   >> at first.   
   >> Except if there is a bad cluster in there (a cluster flagged as bad   
   >> while the file system was running).   
   >>             _________________________________________________   
   >>            /                      
   Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  \    4096   
   >> byte   
   >>           X   512   512   512   512   512   512     
   512   512   X   
   >> cluster on   
   >>            \              XXX       
   Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  /    OS   
   >> C: partition   
   >>             ------------------------------------------------   
   >>   
   >>             If any sector is bad, the cluster is marked bad.   
   >>             The "cluster" is a unit of storage in NTFS.   
   >>   
   >>     Paul   
   >>   
   > More reason to keep a spare Win7 machine /disk around huh.   
   >   
      
   What is Linux version of disk-check? In windows it takes hours as stated   
   above but what about Ubuntu?? What command to use to check this?   
      
   I have a 2 TB disk that is slow and showing signs of wear & tear so I   
   tried to clone it on a new SSD 1TB disk. Acronis states that it is   
   possible to clone on to a smaller disk as long as the actual data is not   
   more than the size of the target disk. The source has about 350GB of   
   data (out of 2TB disk size) but this can't be cloned because the disk   
   has bad clusters according to Acronis. So how do I correct this in Linux   
   ubuntu?   
      
   x-posted to ubuntu as well just in case they can respond quickly.   
      
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