Re: automating 'fsck -y' after a power failure
Joachim Schipper wrote: >>> make a dump of the partition before going to execute potentially data >>> destroying actions? >> yes, this is sound advice of course. but what are you going >> to do with the dump if say, fsck is not able to revive the fs? >> "dump" it back, run fsck again and answer "no" at a couple of >> fsck prompts? how is it going to change anything in the end? > > Well, if fsck can't revive your partition, you can always try different > tools. Something like fsdb may be able to recover part or all of your > filesystem even in cases where fsck loses the plot. Also, fsck may fail in the middle due to lack of memory, so moving the dump to a bigger box to make it run through may be a good solution in that case. Or old fsck fails where a -current fsck won't.
Re: automating 'fsck -y' after a power failure
On Sun, Oct 4, 2009 at 3:10 AM, Anthony Roberts wrote: > What I tend to do for those is just make the filesystems for that machine > read-only. > > This is inconvenient to set up/use for several reasons, but it helps make > machines indifferent to surprise reboots. It's handy if the site has > unreliable power (eg solar/battery out in the bush somewhere) or even > simply because people don't realize random Soekris boxes in wiring cabinets > might need to be shut down cleanly. > > -Anthony > > On Sat, 3 Oct 2009 11:14:16 -0300, "Jose Fragoso" > > wrote: >> Hi, >> >>> If that was a wisething to do, we would have already done so. In other >>> words, it is not wise. It's foolish. >>> >>> -Otto >> >> I totally agree with you. This should not be in the release. >> >> However, I have a few obsd boxes working at places where I can >> not reach with ease. What I want to avoid is telling a client >> (who does not know anything about unix or Xbsd), by phone, to >> run 'fsck -y', when the system does not boot, as a last resource, >> before I have to go there myself. Sometimes, not even a console >> is available. >> >> Thanks for your insight. >> >> Regards, >> >> Jose > > I agree with Anthony here - make root read only, mfs /dev, and mount everything else as nosuid,nodev. If you think you're going to need to add things to it at some point in the future, keep fstab the same, create a directory, add changes to that, then run a script from /etc/rc.securelevel to merge changes and remount root as readonly. It is good to have a throwaway server to test these things on before applying them to a production box. A script to do the above would look something like this in my head (assuming your staging directory is /usr/tmp/staging: cat >/usr/local/sbin/merge-staging <
Re: automating 'fsck -y' after a power failure
On Sun, Oct 4, 2009 at 11:26 AM, bofh wrote: > What does fsck mean? > Filesystem check.
Re: automating 'fsck -y' after a power failure
On Sun, Oct 04, 2009 at 07:58:06PM +0200, frantisek holop wrote: > hmm, on Fri, Oct 02, 2009 at 10:49:56PM +0200, Otto Moerbeek said that > > > here's the thing: even though every single diagnostic message > > > fsck may produce is documented in /usr/share/doc/smm/03.fsck_ffs > > > i dont see how these questions help at all. what i mean is, > > > there is nothing to compare the diagnostic data to anyway, so > > > what is the answer going to be based on? so far i have always > > > only took the leap of faith and pressed yes or always.. what > > > else is there to do? > > > > make a dump of the partition before going to execute potentially data > > destroying actions? > > yes, this is sound advice of course. but what are you going > to do with the dump if say, fsck is not able to revive the fs? > "dump" it back, run fsck again and answer "no" at a couple of > fsck prompts? how is it going to change anything in the end? Well, if fsck can't revive your partition, you can always try different tools. Something like fsdb may be able to recover part or all of your filesystem even in cases where fsck loses the plot. There is also the Sleuth kit. And if all else fails, you can always write your own software/grep through the raw disk/etc. fsck is great at what it does, but it's not the only game in town. Needless to say, restoring from backup is easier than reconstructing a filesystem from a hex dump of the disk. But sometimes you don't have backups... Joachim
Re: automating 'fsck -y' after a power failure
What does fsck mean? I always thought it was those strange bearded sysadmins private cuss word as they always seem to scream *fsck yes damnit!!!* whenever the system crashes On 10/2/09, frantisek holop wrote: > hmm, on Fri, Oct 02, 2009 at 07:31:39PM +0200, Otto Moerbeek said that >> > fsck -y >> > >> > after a power or other type of failure, >> > in cases the automatic file system check fails? >> >> If that was a wisething to do, we would have already done so. In other >> words, it is not wise. It's foolish. > > as usually, i absolutely agree with you Otto. > > however. > > please all the people in the room raise their hands who have the > faintest idea about what 95% of the questions that fsck is going to ask > them on a seriously borked fs mean. my hat goes off to them. > > here's the thing: even though every single diagnostic message > fsck may produce is documented in /usr/share/doc/smm/03.fsck_ffs > i dont see how these questions help at all. what i mean is, > there is nothing to compare the diagnostic data to anyway, so > what is the answer going to be based on? so far i have always > only took the leap of faith and pressed yes or always.. what > else is there to do? > > a couple of months ago, after a certain incident on my notebook > i was presented with a borked suberblock and after i have > figured out that the backup superblock were usable, i just > crossed my fingers and after a dry run i started fsck. > > i got some 7700 'UNKNOWN FILE TYPE's, an unallocated root inode, > bad magic numbers for CGs and fsck messages i have never had the > luck meeting with before... (should read 03.fsck_ffs one of > these days probably -- but even then, i would just say yes > on every question) > > unfortunately i dont have a transcript of that fsck session, > i do however have a "screenshot" of the last phase: > > ** Phase 5 - Check Cyl groups > CG 0: BAD MAGIC NUMBER > FREE BLK COUNT(S) WRONG IN SUPERBLK > SALVAGE? yes > > SUMMARY INFORMATION BAD > SALVAGE? yes > > BLK(S) MISSING IN BIT MAPS > SALVAGE? yes > > 118774 files, 4966785 used, 2542705 free (17073 frags, 315704 blocks, 0.2% > fragmentation) > > UPDATE STANDARD SUPERBLOCK? yes > > > MARK FILE SYSTEM CLEAN? yes > > > * FILE SYSTEM WAS MODIFIED * > > (for the curious: all my files survived under lost+found. i was > as happy as it can be) > > if fsck thinks there is a problem, there is nothing left but to press y > anyway. although i'd very much like to read stories of other admins > doing otherwise. > > -f > -- > atheism is a non-prophet organization. > > -- Sent from my mobile device http://www.glumbert.com/media/shift http://www.youtube.com/watch?v=tGvHNNOLnCk "This officer's men seem to follow him merely out of idle curiosity." -- Sandhurst officer cadet evaluation. "Securing an environment of Windows platforms from abuse - external or internal - is akin to trying to install sprinklers in a fireworks factory where smoking on the job is permitted." -- Gene Spafford learn french: http://www.youtube.com/watch?v=30v_g83VHK4
Re: automating 'fsck -y' after a power failure
On Sun, Oct 04, 2009 at 07:58:06PM +0200, frantisek holop wrote: > hmm, on Fri, Oct 02, 2009 at 10:49:56PM +0200, Otto Moerbeek said that > > > here's the thing: even though every single diagnostic message > > > fsck may produce is documented in /usr/share/doc/smm/03.fsck_ffs > > > i dont see how these questions help at all. what i mean is, > > > there is nothing to compare the diagnostic data to anyway, so > > > what is the answer going to be based on? so far i have always > > > only took the leap of faith and pressed yes or always.. what > > > else is there to do? > > > > make a dump of the partition before going to execute potentially data > > destroying actions? > > yes, this is sound advice of course. but what are you going > to do with the dump if say, fsck is not able to revive the fs? > "dump" it back, run fsck again and answer "no" at a couple of > fsck prompts? how is it going to change anything in the end? > You have several options: consult an expert and indeed answer n to some of the prompts, mount -f the fs and recover your most important files, use the image as a test case to improve fsck_ffs... there are probably more cases why having a dump of the inconsistent fs can be good. -Otto
Re: automating 'fsck -y' after a power failure
hmm, on Fri, Oct 02, 2009 at 10:49:56PM +0200, Otto Moerbeek said that > > here's the thing: even though every single diagnostic message > > fsck may produce is documented in /usr/share/doc/smm/03.fsck_ffs > > i dont see how these questions help at all. what i mean is, > > there is nothing to compare the diagnostic data to anyway, so > > what is the answer going to be based on? so far i have always > > only took the leap of faith and pressed yes or always.. what > > else is there to do? > > make a dump of the partition before going to execute potentially data > destroying actions? yes, this is sound advice of course. but what are you going to do with the dump if say, fsck is not able to revive the fs? "dump" it back, run fsck again and answer "no" at a couple of fsck prompts? how is it going to change anything in the end? -f -- forget everything, as one day everything will forget you.
Re: automating 'fsck -y' after a power failure
What I tend to do for those is just make the filesystems for that machine read-only. This is inconvenient to set up/use for several reasons, but it helps make machines indifferent to surprise reboots. It's handy if the site has unreliable power (eg solar/battery out in the bush somewhere) or even simply because people don't realize random Soekris boxes in wiring cabinets might need to be shut down cleanly. -Anthony On Sat, 3 Oct 2009 11:14:16 -0300, "Jose Fragoso" wrote: > Hi, > >> If that was a wisething to do, we would have already done so. In other >> words, it is not wise. It's foolish. >> >> -Otto > > I totally agree with you. This should not be in the release. > > However, I have a few obsd boxes working at places where I can > not reach with ease. What I want to avoid is telling a client > (who does not know anything about unix or Xbsd), by phone, to > run 'fsck -y', when the system does not boot, as a last resource, > before I have to go there myself. Sometimes, not even a console > is available. > > Thanks for your insight. > > Regards, > > Jose
Re: automating 'fsck -y' after a power failure
Hi, > If that was a wisething to do, we would have already done so. In other > words, it is not wise. It's foolish. > > -Otto I totally agree with you. This should not be in the release. However, I have a few obsd boxes working at places where I can not reach with ease. What I want to avoid is telling a client (who does not know anything about unix or Xbsd), by phone, to run 'fsck -y', when the system does not boot, as a last resource, before I have to go there myself. Sometimes, not even a console is available. Thanks for your insight. Regards, Jose -- An Excellent Credit Score is 750 See Yours in Just 2 Easy Steps!
Re: automating 'fsck -y' after a power failure
Otto Moerbeek wrote: Note that I said "dump the partition", not "dump the filesystem". Oops. you mean dd(1)... sorry for the noise -- Mauro Rezzonico , Como, Italia "Maybe this world is another planet's hell" - H.Huxley
Re: automating 'fsck -y' after a power failure
On Sat, Oct 03, 2009 at 12:12:39AM +0200, Mauro Rezzonico wrote: > Otto Moerbeek wrote: > >make a dump of the partition before going to execute potentially data > >destroying actions? > > So you can dump a botched filesystem? The manpage says nothing about that... > Well it doesn't say the contrary but... > > So, question is: Can you *really* dump a "borked fs"? Note that I said "dump the partition", not "dump the filesystem". -Otto
Re: automating 'fsck -y' after a power failure
On Sat, 03 Oct 2009 00:12:39 +0200 Mauro Rezzonico wrote: > Otto Moerbeek wrote: > > make a dump of the partition before going to execute potentially > > data destroying actions? > > So you can dump a botched filesystem? The manpage says nothing about > that... Well it doesn't say the contrary but... > > So, question is: Can you *really* dump a "borked fs"? > Think 'dd', to have a second chance at messing up the data, or work from the image to restore files. (See what i did there? ;) -Robert
Re: automating 'fsck -y' after a power failure
Otto Moerbeek wrote: make a dump of the partition before going to execute potentially data destroying actions? So you can dump a botched filesystem? The manpage says nothing about that... Well it doesn't say the contrary but... So, question is: Can you *really* dump a "borked fs"? -- Mauro Rezzonico , Como, Italia "Maybe this world is another planet's hell" - H.Huxley
Re: automating 'fsck -y' after a power failure
On Fri, Oct 02, 2009 at 10:38:16PM +0200, frantisek holop wrote: > hmm, on Fri, Oct 02, 2009 at 07:31:39PM +0200, Otto Moerbeek said that > > > fsck -y > > > > > > after a power or other type of failure, > > > in cases the automatic file system check fails? > > > > If that was a wisething to do, we would have already done so. In other > > words, it is not wise. It's foolish. > > as usually, i absolutely agree with you Otto. > > however. > > please all the people in the room raise their hands who have the > faintest idea about what 95% of the questions that fsck is going to ask > them on a seriously borked fs mean. my hat goes off to them. > > here's the thing: even though every single diagnostic message > fsck may produce is documented in /usr/share/doc/smm/03.fsck_ffs > i dont see how these questions help at all. what i mean is, > there is nothing to compare the diagnostic data to anyway, so > what is the answer going to be based on? so far i have always > only took the leap of faith and pressed yes or always.. what > else is there to do? make a dump of the partition before going to execute potentially data destroying actions? -Otto > > a couple of months ago, after a certain incident on my notebook > i was presented with a borked suberblock and after i have > figured out that the backup superblock were usable, i just > crossed my fingers and after a dry run i started fsck. > > i got some 7700 'UNKNOWN FILE TYPE's, an unallocated root inode, > bad magic numbers for CGs and fsck messages i have never had the > luck meeting with before... (should read 03.fsck_ffs one of > these days probably -- but even then, i would just say yes > on every question) > > unfortunately i dont have a transcript of that fsck session, > i do however have a "screenshot" of the last phase: > > ** Phase 5 - Check Cyl groups > CG 0: BAD MAGIC NUMBER > FREE BLK COUNT(S) WRONG IN SUPERBLK > SALVAGE? yes > > SUMMARY INFORMATION BAD > SALVAGE? yes > > BLK(S) MISSING IN BIT MAPS > SALVAGE? yes > > 118774 files, 4966785 used, 2542705 free (17073 frags, 315704 blocks, 0.2% > fragmentation) > > UPDATE STANDARD SUPERBLOCK? yes > > > MARK FILE SYSTEM CLEAN? yes > > > * FILE SYSTEM WAS MODIFIED * > > (for the curious: all my files survived under lost+found. i was > as happy as it can be) > > if fsck thinks there is a problem, there is nothing left but to press y > anyway. although i'd very much like to read stories of other admins > doing otherwise. > > -f > -- > atheism is a non-prophet organization.
Re: automating 'fsck -y' after a power failure
On Fri, Oct 2, 2009 at 4:38 PM, frantisek holop wrote: > if fsck thinks there is a problem, there is nothing left but to press y > anyway. B although i'd very much like to read stories of other admins > doing otherwise. Put a rock on the 'y' key and go get some coffee.
Re: automating 'fsck -y' after a power failure
hmm, on Fri, Oct 02, 2009 at 07:31:39PM +0200, Otto Moerbeek said that > > fsck -y > > > > after a power or other type of failure, > > in cases the automatic file system check fails? > > If that was a wisething to do, we would have already done so. In other > words, it is not wise. It's foolish. as usually, i absolutely agree with you Otto. however. please all the people in the room raise their hands who have the faintest idea about what 95% of the questions that fsck is going to ask them on a seriously borked fs mean. my hat goes off to them. here's the thing: even though every single diagnostic message fsck may produce is documented in /usr/share/doc/smm/03.fsck_ffs i dont see how these questions help at all. what i mean is, there is nothing to compare the diagnostic data to anyway, so what is the answer going to be based on? so far i have always only took the leap of faith and pressed yes or always.. what else is there to do? a couple of months ago, after a certain incident on my notebook i was presented with a borked suberblock and after i have figured out that the backup superblock were usable, i just crossed my fingers and after a dry run i started fsck. i got some 7700 'UNKNOWN FILE TYPE's, an unallocated root inode, bad magic numbers for CGs and fsck messages i have never had the luck meeting with before... (should read 03.fsck_ffs one of these days probably -- but even then, i would just say yes on every question) unfortunately i dont have a transcript of that fsck session, i do however have a "screenshot" of the last phase: ** Phase 5 - Check Cyl groups CG 0: BAD MAGIC NUMBER FREE BLK COUNT(S) WRONG IN SUPERBLK SALVAGE? yes SUMMARY INFORMATION BAD SALVAGE? yes BLK(S) MISSING IN BIT MAPS SALVAGE? yes 118774 files, 4966785 used, 2542705 free (17073 frags, 315704 blocks, 0.2% fragmentation) UPDATE STANDARD SUPERBLOCK? yes MARK FILE SYSTEM CLEAN? yes * FILE SYSTEM WAS MODIFIED * (for the curious: all my files survived under lost+found. i was as happy as it can be) if fsck thinks there is a problem, there is nothing left but to press y anyway. although i'd very much like to read stories of other admins doing otherwise. -f -- atheism is a non-prophet organization.
Re: automating 'fsck -y' after a power failure
On Fri, Oct 02, 2009 at 09:15:41AM -0300, Jose Fragoso wrote: > Hi, > > Is it possible to automate the process of > running > > fsck -y > > after a power or other type of failure, > in cases the automatic file system check fails? If that was a wisething to do, we would have already done so. In other words, it is not wise. It's foolish. -Otto
Re: automating 'fsck -y' after a power failure
Jose, this is an ugly modification in /etc/rc but it should do what you need. Search for the line that starts with 8) and modify it to look like this: 8) echo "Corro FSCK de emergencia..." fsck -y ; fsck_st=$? if [ $fsck_st != 0 ]; then echo "Automatic file system check failed; help!" exit 1 fi ;; Regards, Marcos Jose Fragoso wrote: Hi, Is it possible to automate the process of running fsck -y after a power or other type of failure, in cases the automatic file system check fails? Thanks in advance. Regards, Jose -- An Excellent Credit Score is 750 See Yours in Just 2 Easy Steps!
automating 'fsck -y' after a power failure
Hi, Is it possible to automate the process of running fsck -y after a power or other type of failure, in cases the automatic file system check fails? Thanks in advance. Regards, Jose -- An Excellent Credit Score is 750 See Yours in Just 2 Easy Steps!
