August 19, 201114 yr I've managed to accidentally move a file to /dev/sda and now need to delete it. However I am unable to gain access to /dev/sda as it returns "Permission Denied", can anyone tell me how to get access to it in order to delete the file? Thanks.
August 19, 201114 yr I've managed to accidentally move a file to /dev/sda and now need to delete it. However I am unable to gain access to /dev/sda as it returns "Permission Denied", can anyone tell me how to get access to it in order to delete the file? Thanks. /dev/sda would normally be one of your raw disk devices. (might be your flash drive, or one of your SATA disks) Only way for us to know is for you to attach a copy of your syslog for analysis to your next post. In any case, you might want to describe what specific exact command you used to move the file. (since /dev/sda will not have a file system, odds are you clobbered the master-boot-record on that device and overwrote it. You might have some damage to fix.) You can get a listing of the devices on your server by typing ls -l /dev/disk/by-id post the output here. Joe L.
August 19, 201114 yr Author Hmm, that doesn't sound good. I believe the command was mv filename /dev/sda Syslog from the currently running server is attached. Requested output is also attached. Thanks. output.txt syslog-2011-08-19.txt
August 19, 201114 yr Where are you actually seeing this file that you moved?? My guess is you put something into the file system stored in ram so a reboot would fix it. Peter
August 19, 201114 yr Where are you actually seeing this file that you moved?? My guess is you put something into the file system stored in ram so a reboot would fix it. Peter /dev/sda is not in RAM. It is the raw device reference and the MBR may be damaged.
August 19, 201114 yr /dev/sda is your disk1. Aug 18 23:39:26 NAS kernel: md: import disk0: [8,32] (sdc) WDC WD20EARX-00P WD-WCAZA6580478 size: 1953514552 Aug 18 23:39:26 NAS kernel: md: import disk1: [8,0] (sda) WDC WD20EARS-00M WD-WCAZA3646980 size: 1953514552 Aug 18 23:39:26 NAS kernel: md: import disk2: [8,16] (sdb) WDC WD10EADS-11M WD-WCAV53474284 size: 976762552 You've clobbered its MBR, that is certain, but you are in luck... you can get it re-constructed by unRAID by Stopping the array un-assign disk1 start the array with it un-assigned stop the array once more re-assign disk1 Start the array and let unRAID re-construct it. Unfortunately, the file itself is gone. (since you moved it). Joe L.
August 19, 201114 yr What evidence suggests the MBR is actually clobbered? I don't see the disk being disabled due to the partition missing. It still wouldn't surprize me if you somehow just copied the files into the ram file system. In either case, try an array stop and re-start. If the disks all appear fine then there was likely no damage done. Peter
August 19, 201114 yr What evidence suggests the MBR is actually clobbered? I don't see the disk being disabled due to the partition missing. It still wouldn't surprize me if you somehow just copied the files into the ram file system. In either case, try an array stop and re-start. If the disks all appear fine then there was likely no damage done. Peter don't need to do that to verify. Type fdisk -l /dev/sda and see what it prints. and type dd if=/dev/sda count=1 | od -x -A d Nobody's looked at the MBR since the system was booted. That is probably why it is still working. A quick question... How big was the file you moved to /dev/sda? Joe L.
August 20, 201114 yr Author Type fdisk -l /dev/sda and see what it prints. and type dd if=/dev/sda count=1 | od -x -A d The output for both these commands is attached. A quick question... How big was the file you moved to /dev/sda? I think it was around 370MB, and the file itself was not important, I don't care if it is lost. I haven't done the rebuild yet, am I right to go ahead and do it now?? I assume it will to take a while to reconstruct?? There is 1.5TB of data on the disk. I should also mention the server appears to be functioning fine. It has been powered off twice since the file was moved. Data from that disk still shows up in the user shares and can be read. I haven't written to the disk yet incase it overwrites existing data or something. Thanks, Ash Output.txt
August 20, 201114 yr Type fdisk -l /dev/sda and see what it prints. and type dd if=/dev/sda count=1 | od -x -A d The output for both these commands is attached. A quick question... How big was the file you moved to /dev/sda? I think it was around 370MB, and the file itself was not important, I don't care if it is lost. I haven't done the rebuild yet, am I right to go ahead and do it now?? I assume it will to take a while to reconstruct?? There is 1.5TB of data on the disk. I should also mention the server appears to be functioning fine. It has been powered off twice since the file was moved. Data from that disk still shows up in the user shares and can be read. I haven't written to the disk yet incase it overwrites existing data or something. Thanks, Ash Definitely, go through the steps I outlined. The file was too large to not have caused damage. Stop the array, un-assign the disk Start the array with it un-assigned Stop the array again re-assign the disk to its same slot in the array. let it reconstruct. (This will take about as long as your original parity calculation) Joe L.
August 20, 201114 yr The data from the last commands you posted is correct for a 2T drive with the partition starting on sector 63. I'm not seeing any damage done to the MBR. Peter
August 20, 201114 yr The data from the last commands you posted is correct for a 2T drive with the partition starting on sector 63. I'm not seeing any damage done to the MBR. Peter I don't either... Interesting.
August 23, 201114 yr Author The rebuild is just about to finish (just under an hour left). Is there anything else I need to do once it is done, or is it good to go?? Do I need to do a parity check?? Thanks, Ash
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