Date: Tue, 20 Sep 2022 16:47:40 +1000 From: Ian Smith <smithi@nimnet.asn.au> To: grarpamp <grarpamp@gmail.com> Cc: Gary Aitken <freebsd@dreamchaser.org>,questions@freebsd.org Subject: Re: disk non-destructive bad-block write/fix? Message-ID: <AA23BE19-C587-4D60-81DA-4695DC2E6421@nimnet.asn.au> In-Reply-To: <CAD2Ti28Bdm9kZq5umziXPizMXQdV5LZkYixogWmR0=6CBaM11w@mail.gmail.com> References: <d687eb29-a3fb-7d91-a2c6-c1e4e1dc7e31@dreamchaser.org> <CAD2Ti28Bdm9kZq5umziXPizMXQdV5LZkYixogWmR0=6CBaM11w@mail.gmail.com>
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On 20 September 2022 3:45:55 pm AEST, grarpamp <grarpamp@gmail=2Ecom> wrote= : > > throwing a lot of errors >=20 > USB=2E=2E=2E reseat cables=2E Or try another one/s, if external=2E But first I'd skip to your last point ie read testing, which also could ca= tch a bad cable=2E If it's just or mainly that, much angst relieved=2E > > Is there a way to exercise the free blocks on a ufs disk and move > all > > defective ones to the bad-block list? >=20 > That's function of the hw, not the fs=2E Unless the disk is really ancient, ISTR badblocks(ono) from 2=2E6-REL days= =2E > If you want to nuke the fs and do that to the disk > dd if=3D/dev/urandom of=3D/dev/da0 bs=3D1m >=20 > If not, then you can pray to hit most of the fs data areas with > dd if=3D/dev/urandom of=3D/mnt/bigrandfile bs=3D1m >=20 > but that's a prayer=2E And closer to last resort =2E=2E=2E > Better to buy enough media to have backups of backups=2E Ack, and it's so cheap these days=2E > > Or is that already happening in the above scenario? >=20 > Yes most firmwares modepages are set to automatically > write-reallocate, you can fiddle those using the scsi/ata/usb > spec and camcontrol=2E >=20 > Store a sha256 of all the files, > read them back to verify and compare to that=2E >=20 > > The disk is about 40% full >=20 > There's probably not a shrinkfs, and without checking where those > existing extents are, attempting to create a tailing 60% fs to > move the 40% into to write-realloc it=2E=2E=2E could end up footshot=2E Again, be sure cables are good before such desperate measures=2E > > wondering if the whole rest of it is trashed >=20 > dd if=3D/dev/da0 of=3D/dev/null bs=3D1m conv=3Dnoerror >=20 > But that's only a read test, not a write test=2E But nice and safe, for starters - and with noerror reporting all bad bits= =2E cheers, Ian
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