On Fri, March 10, 2017 9:52 am, Warren Young wrote:> On Mar 10, 2017, at 6:32 AM, James B. Byrne <byrnejb at harte-lyne.ca> wrote: >> >> On Thu, March 9, 2017 09:46, John Hodrien wrote: >>> >>> fsck's not good at finding disk errors, it finds filesystem errors. >> >> If not fsck then what? > > badblocks(8).And I definitely will unmount relevant filesystem(s) before using badblocks...> > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos >++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++
On Mar 10, 2017, at 9:28 AM, Valeri Galtsev <galtsev at kicp.uchicago.edu> wrote:> > > On Fri, March 10, 2017 9:52 am, Warren Young wrote: >> On Mar 10, 2017, at 6:32 AM, James B. Byrne <byrnejb at harte-lyne.ca> wrote: >>> >>> On Thu, March 9, 2017 09:46, John Hodrien wrote: >>>> >>>> fsck's not good at finding disk errors, it finds filesystem errors. >>> >>> If not fsck then what? >> >> badblocks(8). > > And I definitely will unmount relevant filesystem(s) before using > badblocks?You don?t necessarily have to. The default mode of badblocks is a non-invasive read-only test which is safe to run on a mounted filesystem. That said, a read-only badblocks pass can give a false ?no errors? report in cases where a non-destructive read-then-write pass (-n) will show errors. Alternatively, a read-only pass may show an error that a read-then-write pass will silently bury by forcing the drive to relocate the bad sector. In extreme cases, you could potentially fix a problem with a read-random-random-write pass (-n -t random -t random) because that will statistically flip all the bits at least twice, which may rub the drive?s nose in a bad sector, forcing a reallocation where a normal read-then-write pass (-n alone) may not. Hard drives are weird. It is only through the grace of ECC and such that they approximate deterministic behavior as well as they do.
I get up around 0630, u can come anytime after that. I want to hit the range that morning but if I KNEW when you are arriving, I could plan around that...> On Mar 10, 2017, at 9:28 AM, Valeri Galtsev <galtsev at kicp.uchicago.edu> wrote: >> >> >> On Fri, March 10, 2017 9:52 am, Warren Young wrote: >>> On Mar 10, 2017, at 6:32 AM, James B. Byrne <byrnejb at harte-lyne.ca> wrote: >>>> >>>> On Thu, March 9, 2017 09:46, John Hodrien wrote: >>>>> >>>>> fsck's not good at finding disk errors, it finds filesystem errors. >>>> >>>> If not fsck then what? >>> >>> badblocks(8). >> >> And I definitely will unmount relevant filesystem(s) before using >> badblocks??? > > You don???t necessarily have to. The default mode of badblocks is a non-invasive read-only test > which is safe to run on a mounted filesystem. > > That said, a read-only badblocks pass can give a false ???no errors??? report in cases where a > non-destructive read-then-write pass (-n) will show errors. > > Alternatively, a read-only pass may show an error that a read-then-write pass will silently bury > by forcing the drive to relocate the bad sector. > > In extreme cases, you could potentially fix a problem with a read-random-random-write pass (-n -t > random -t random) because that will statistically flip all the bits at least twice, which may rub > the drive???s nose in a bad sector, forcing a reallocation where a normal read-then-write pass (-n > alone) may not. > > Hard drives are weird. It is only through the grace of ECC and such that they approximate > deterministic behavior as well as they do. > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos >