Matthias Andree wrote:> Greetings, > > out of fun and to investigate claims about alleged bgfsck resource > hogging (which I could not reproduce) posted to > news:de.comp.os.unix.bsd, I pressed the reset button on a live FreeBSD > 5-STABLE system. > > Upon reboot, fsck -p complained about an unexpected softupdates > inconsistency on the / file system and put me into single user mode, the > manual fsck / then asked me to agree to increasing a link count from 21 > to 22 (and later to fix the summary, which I consider a non-issue). A > subsequent fsck -p / ended with no abnormality detected. > > Unfortunately, I haven't copied the details, assuming they would be > copied into the log, but they haven't. > > Is this a situation the current 5-STABLE softupdates code (on a UFS1 FS > that I kept from FreeBSD 4) is allowed to cause? > > Is that a bug in the file system, say, write ordering goofed up? > > Or is that a bug in the firmware of my disk drive (Western Digital > Caviar AC420400D, a rebranded IBM DJNA drive)? I gather that ATA drives > are supposed to flush their caches on software (command) and hardware > resets (reset line active). > > I did not power cycle. >No, this in theory should not happen. YOu could have caught it right at the instance that it was sending a transaction out to disk, or you could have caught an edge case that isn't understood yet. Unfortunately, ATA drives also cannot be trusted to flush their caches when one would expect, so this leaves open a lot of possible causes for your problem. Scott _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"
Greetings, out of fun and to investigate claims about alleged bgfsck resource hogging (which I could not reproduce) posted to news:de.comp.os.unix.bsd, I pressed the reset button on a live FreeBSD 5-STABLE system. Upon reboot, fsck -p complained about an unexpected softupdates inconsistency on the / file system and put me into single user mode, the manual fsck / then asked me to agree to increasing a link count from 21 to 22 (and later to fix the summary, which I consider a non-issue). A subsequent fsck -p / ended with no abnormality detected. Unfortunately, I haven't copied the details, assuming they would be copied into the log, but they haven't. Is this a situation the current 5-STABLE softupdates code (on a UFS1 FS that I kept from FreeBSD 4) is allowed to cause? Is that a bug in the file system, say, write ordering goofed up? Or is that a bug in the firmware of my disk drive (Western Digital Caviar AC420400D, a rebranded IBM DJNA drive)? I gather that ATA drives are supposed to flush their caches on software (command) and hardware resets (reset line active). I did not power cycle. -- Matthias Andree _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"
In the last episode (Nov 24), Scott Long said:> Matthias Andree wrote: > > out of fun and to investigate claims about alleged bgfsck resource > > hogging (which I could not reproduce) posted to > > news:de.comp.os.unix.bsd, I pressed the reset button on a live > > FreeBSD 5-STABLE system. > > > > Upon reboot, fsck -p complained about an unexpected softupdates > > inconsistency on the / file system and put me into single user > > mode, the manual fsck / then asked me to agree to increasing a link > > count from 21 to 22 (and later to fix the summary, which I consider > > a non-issue). A subsequent fsck -p / ended with no abnormality > > detected. > > No, this in theory should not happen. YOu could have caught it right > at the instance that it was sending a transaction out to disk, or you > could have caught an edge case that isn't understood yet. > Unfortunately, ATA drives also cannot be trusted to flush their > caches when one would expect, so this leaves open a lot of possible > causes for your problem.If you just want to test stability in the face of system crashes (and not power failure), you can drop to DDB and run "reboot" to simulate a panic (or run reboot -qn as root). That way your drive doesn't lose power. That said, I get unexpected softupdates inconsistencies pretty regularly on kernel panics. I just let the system run until I can reboot and run a fsck -p. -- Dan Nelson dnelson@allantgroup.com