<div dir="ltr">Doh! As I described, and not as the command line I re-typed. It was:<div><br><div># ddrescue /dev/sdc /run/media/danielm/goodexternalcaddy/failingdisk.img /root/failingdisk.mapfile</div><div># ddrescue -r3 /dev/sdc /run/media/danielm/goodexternalcaddy/failingdisk.img /root/failingdisk.mapfile</div><div><br></div><div>Just in case anyone needs to try this kind of recovery in the future. The mapfile is really important, as that is how GNU ddrescue minimises reads from broken portions in the initial pass (max data, min more damage) and then retries just those parts in the second invocation.</div><div><br></div><div> Daniel</div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, 22 Apr 2021 at 12:23, Daniel Morris <<a href="mailto:danielmorris.cengmiet@gmail.com">danielmorris.cengmiet@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Sorry about the very late reminder, enabled by realising my swlug list email now goes through gmail instead of POP to my broken disk..<div><br></div><div>I spent a head-banging day yesterday scrabbling through backups</div><div>Realised that my flaky data is on a wholly LVM managed disk</div><div>Made enough room to drag data off the complete disk, rather than 200G "partition" I thought I was messing with (LV)</div><div>Finding the writes (ddrescue) to other internal disks spawn SATA errors themselves that bring those disks down to read-only</div><div>Having a sulk/pity-party for one</div><div>Leaping on colleague's suggestion that I swap the failing disk into one of the external caddies to try again with my other system (rather than do the system surgery):</div><div><br></div><div># dd_rescue /dev/sdc /run/media/danielm/goodexternalcaddy/failingdisk.img /root/failingdisk.mapfile</div><div># dd_rescue -r3 /dev/sdc /run/media/danielm/goodexternalcaddy/failingdisk.img /root/failingdisk.mapfile<br></div><div><br></div><div>ddrescue (that's GNU/gddrescue, not dd_rescue) sucked all ~720GiB off in one run with zero read errors overnight through my laptop, out to another external backup disk which was plugged into the laptop's other USB port, which gave me hope. After storing the flaky disk, I re-mounted my good external caddy to try working on the image:</div><div><br></div><div># losetup -r /dev/loop1 /run/media/danielm/goodexternalcaddy/failingdisk.img<br></div><div><br></div><div>I've just mounted the image (ro) on a loopback device and openSUSE's LVM automagically scanned, detected the volume groups, but a simple mount has failed complaining that it "<span style="color:rgb(0,0,0);font-family:monospace">can't read superblock". </span></div><div><br></div><div>I expect it may be a bit confused as the journal shows a device mapper has misidentified a FAT-fs. Bearing in mind I know have what's probably an ext2 structure in a logical volume bound inside an image that's mounted over a loopback via USB to an encrypted, probably native XFS store. To just write that sequence down makes me marvel at how clever the layers are.</div><div><br></div><div>I've come full-circle to think that perhaps the disk might be Ok and the issues that first appeared in December are actually down to a failing motherboard and/or SATA expansion cards. I've been holding back the full-scale Ryzen/mobo/m2/graphics/memory/psu swapout since the last of the upgrade bits arrived. I wanted to do a full backup-and-check before diving in...</div><div><br></div><div>Daniel</div><div> </div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, 21 Apr 2021 at 09:18, Clifford Perry via Swlug <<a href="mailto:swlug@mailman.lug.org.uk" target="_blank">swlug@mailman.lug.org.uk</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">I enjoyed my first virtual meet up - thanks all :) <div><br></div><div>Cliff</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Apr 21, 2021 at 8:42 AM Dick Bain via Swlug <<a href="mailto:swlug@mailman.lug.org.uk" target="_blank">swlug@mailman.lug.org.uk</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto">Humble apologies for not seeing this until this morning, knackered after a day in the garden is my only excuse 😉<div dir="auto">Hopefully see you all next month</div><div dir="auto">Dick</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, 20 Apr 2021, 18:28 Daniel Morris via Swlug, <<a href="mailto:swlug@mailman.lug.org.uk" target="_blank">swlug@mailman.lug.org.uk</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">It's the third Tuesday in the month, so 7pm tonight will be<br>SWLUG-time! We're going to meet again using Jitsi.<br><br>Simply launch a web-browser and go to<br><br><a href="https://meet.jit.si/swlugmeetonline" rel="noreferrer" target="_blank">https://meet.jit.si/swlugmeetonline</a><br><br>Or,<br><a href="https://jitsi.org/jitsi-meet/" rel="noreferrer" target="_blank">https://jitsi.org/jitsi-meet/</a> and choose "Start a call" and enter<br>"swlugmeetonline" as the name.<br><br>Join me to grumble about yet another failing disk and another emergency backup that is taking forever, the wonders of Ryzen, the fantabulousness of vaccines, or whatever...<br><br> Daniel</div>
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