<html><head></head><body style="zoom: 0%;"><div dir="auto">"but shouldn't we perhaps leave it up to the end user / owner of the </div> <div dir="auto">hardware, to decide when it's ready for the recycle bin ?" </div> <div dir="auto">with hard drives (forget SSDs, they are hardware accelerators absolutely unaffordable for data storing) it is not the user/owner that decide it , unless he doesn't want to suicide his data </div> <div dir="auto">is the SMART system that tells you that one first reallocation happen </div> <div dir="auto">Sectors reallocation are not allowed </div> <div dir="auto">Those few 100 or 250 sectors are just for the SMART system </div> <div dir="auto">As soon just one reallocation happen, it is time to waste the drive </div> <div dir="auto">Like with car tyres, when you reach the marker , it is time to waste them, but if you run too few kilometers per year, after few years the gum got dried and you create a risk for yourself and the others if you don waste them </div> <div dir="auto">This comparison applies to hard drives </div> <div dir="auto">If the weekly SMART test tells you that a drive is in pre-failure (just reallocations happen, few mean 3 - 4 - 5) you have been warned: </div> <div dir="auto">it is time to waste "the tyre" </div> <div dir="auto">You don't do that, you was warned </div> <div class="gmail_quote" >Il giorno 12 apr 2023, alle ore 14:37, Roland <<a href="mailto:devzero@web.de" target="_blank">devzero@web.de</a>> ha scritto:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> <pre class="blue"><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;">Reall silly plan - been there years back in time when drives were FAR </blockquote>more expensive with the price per GiB. <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;">Todays - just throw bad drive to recycle bin - it's not worth to do </blockquote>this silliness. ok, i understand your point of view. and thank you for the input. but this applies to a world with endless ressources and when people can afford the new hardware. i think, with the same logic, you can designate some guy to be silly , if he puts a patch on his bicycle inner tube instead of buying a new one, as they are cheap. with the patch, the tube is always worse then a new one. and he probably risks his own health, because of using a tube which may already have gotten porous... but shouldn't we perhaps leave it up to the end user / owner of the hardware, to decide when it's ready for the recycle bin ? or should we perhaps wait for the next harddrive supply crisis (like in 2011)? then people start to get more creative in using what they have, because they have no other option... <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> whenever you want to create new arrangement for you disk with 'bad' </blockquote>areas, <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;">you can always start from 'scratch' - since afterall - lvm2 ONLY </blockquote>manipulates with metadata within disk front - <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;">so if you need to create new 'holes', just 'pvcreate -f', vgcreate, and 'lvcreate -Zn -Wn' and then 'lvextend' with normal or 'lvextend --type error | --type </blockquote>zero' segment types around bad areas with specific size. <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;">Once you are finished and your LV precisely matches your 'previous' </blockquote>LV of you past VG - you can start to use this LV again with <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;">new arrangement of 'broken zeroed/errored' areas. </blockquote> yes, i have already come to the conclusion, that it's always better to start from scratch like this. i dismissed the idea of excluding or relocating bad sectors. <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> But good advice from me - whenever 'smartctl' starts to show </blockquote>relocation block errors - it's the right moment to 'dd_rescue' <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> any LV to your new drive... </blockquote> yes, i'm totally aware that we walk on very thin ice here. but i'd really like to collect some real world data/information on how good such disk "recycling" can probably work. i don't have any pointers for such and did not find any information, on "how fast a bad disk gets worse, if it has irretrievable bad sectors and smart is reporting relocation errors. there seems not much information around for this... i guess such "broken" disks being used with zfs in a redundant setup, they could probable still serve a purpose. maybe not for production data, but probably good enough for "not so important" application. it's a little bit academic project. for my own fun. i like to fiddle with disks, lvm, zfs and that stuff.... roland Am 12.04.23 um 12:20 schrieb Zdenek Kabelac: <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> Dne 09. 04. 23 v 20:21 Roland napsal(a): <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #8ae234; padding-left: 1ex;"> Well, if the LV is being used for anything real, then I don't know of anything where you could remove a block in the middle and still have a working fs. You can only reduce fs'es (the ones that you can reduce) </blockquote> my plan is to scan a disk for usable sectors and map the logical volume around the broken sectors. whenever more sectors get broken, i'd like to remove the broken ones to have a usable lv without broken sectors.</blockquote> Reall silly plan - been there years back in time when drives were FAR more expensive with the price per GiB. Todays - just throw bad drive to recycle bin - it's not worth to do this silliness. HDD bad sectors are spreading - and slowly the surface gets destroyed.... So if you make large 'head-room' around bad disk areas - if they are concentrated on some disk area - and you know topology of you disk drive like i.e. 1% free disk space before and after bad area - you could possibly use disk for a little while more - but only to store invaluable data.... <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> since you need to rebuild your data anyway for that disk, you can also recreate the whole logical volume. my question and my project is a little bit academic. i'd simply want to try out how much use you can have from some dead disks which are trash otherwise... </blockquote> You could always take 'vgcfgbackup' of lvm2 metadata and make some crazy transition of if with even AWK/python/perl - but we really tend to support just some useful features - as there is already 'too much' and users are getting often lost. One very simply & naive implementation could be going alonge this path - whenever you want to create new arrangement for you disk with 'bad' areas, you can always start from 'scratch' - since afterall - lvm2 ONLY manipulates with metadata within disk front - so if you need to create new 'holes', just 'pvcreate -f', vgcreate, and 'lvcreate -Zn -Wn' and then 'lvextend' with normal or 'lvextend --type error | --type zero' segment types around bad areas with specific size. Once you are finished and your LV precisely matches your 'previous' LV of you past VG - you can start to use this LV again with new arrangement of 'broken zeroed/errored' areas. I've some serious doubts about usability of this with any filesystem :) but if you think this has some added value - fell free to use. If the drive you play with would be 'discardable' (SSD/NVMe) then one must take extra care there is no 'discard/TRIM' anywhere in the process - as that would lose all data irrecoverably.... But good advice from me - whenever 'smartctl' starts to show relocation block errors - it's the right moment to 'dd_rescue' any LV to your new drive... <blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> yes, pvmove is the other approach for that. but will pvmove continue/finish by all means when moving extents located on a bad sector ? </blockquote> pvmove CANNOT be used with bad drives - it cannot deal with erroring sectors and basically gets stuck there trying to mirror unrecoverable disk areas... Regards Zdenek</blockquote> <hr> linux-lvm mailing list linux-lvm@redhat.com <a href="https://listman.redhat.com/mailman/listinfo/linux-lvm">https://listman.redhat.com/mailman/listinfo/linux-lvm</a> read the LVM HOW-TO at <a href="http://tldp.org/HOWTO/LVM-HOWTO">http://tldp.org/HOWTO/LVM-HOWTO</a>/ </pre></blockquote></div></body></html>