hello, quite old thread - but damn interesting, though :) > Having the PE number, you can easily do > pvmove /dev/broken:PE /dev/somewhere-else does somebody know if it's possible to easily remap a PE with standard lvm tools, instead of pvmoving it ? trying to move data off from defective sectors can need a very long time, especially when multiple sectors being affected and if the disks are desktop drives. let's think of some "re-partitioning" tool which sets up lvm on top of a disk with bad sectors and which scans/skips&remaps megabyte sized PE's to some spare area, before the disk is being used. badblock remapping at the os level instead at the disks controller level. yes, most of you will tell it's a bad idea but i have a cabinet full of disks with bad sectors and i'd be really be curious how good and how long a zfs raidz would work on top of such "badblocks lvm". at least, i'd like to experiment with that. let's call it academical project for learning purpose and for demonstration of lvm strength :D such "remapping" could look like this: # pvs --segments -ovg_name,lv_name,seg_start_pe,seg_size_pe,pvseg_start -O pvseg_start -S vg_name=VGloop0 VG LV Start SSize Start VGloop0 blocks_good 0 4 0 VGloop0 blocks_bad 1 1 4 VGloop0 blocks_good 5 195 5 VGloop0 blocks_bad 2 1 200 VGloop0 blocks_good 201 699 201 VGloop0 blocks_spare 0 120 900 VGloop0 blocks_good 200 1 1020 VGloop0 blocks_good 4 1 1021 VGloop0 blocks_bad 0 1 1022 blocks_good is LV with healty PE's, blocks_bad is LV with bad PE's and blocks_spare is LV where you take healthy PE's from as a replacement for bad PE's found in blocks_good LV roland sysadmin > linux-lvm] How to handle Bad Block relocation with LVM? > Lars Ellenberg lars.ellenberg at linbit.com > Thu Nov 29 14:04:01 UTC 2012 > > Previous message (by thread): How to handle Bad Block relocation with LVM? > Next message (by thread): How to handle Bad Block relocation with LVM? > Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] > > On Thu, Nov 29, 2012 at 07:26:24AM -0500, Brian J. Murrell wrote: > > On 12-11-28 08:57 AM, Zdenek Kabelac wrote: > > > > > > Sorry, no automated tool. > > > > Pity, > > > > > You could possibly pvmove separated PEs manually with set of pvmove > > > commands. > > > > So, is the basic premise to just find the PE that is sitting on a bad > > block and just pvmove it into an LV created just for the purpose of > > holding PEs that are on bad blocks? > > > > So what happens when I pvmove a PE out of an LV? I take it LVM moves > > the data (or at least tries in this case) on the PE being pvmoved onto > > another PE before moving it? > > > > Oh, but wait. pvmove (typically) moves PEs between physical volumes. > > Can it be used to remap PEs like this? > > So what do you know? > You either know that pysical sector P on some physical disk is broken. > Or you know that logical sector L in some logical volume is broken. > > If you do > pvs --unit s --segment -o vg_name,lv_name,seg_start,seg_size,seg_start_pe,pe_start,seg_pe_ranges > > That should give you all you need to transform them into each other, > and to transform the sector number to PE number. > > Having the PE number, you can easily do > pvmove /dev/broken:PE /dev/somewhere-else > > Or with alloc anywhere even elsewhere on the same broken disk. > # If you don't have an other PV available, > # but there are free "healthy" extents on the same PV: > # pvmove --alloc anywhere /dev/broken:PE /dev/broken > Which would likely not be the smartest idea ;-) > > You should then create one LV named e.g. "BAD_BLOCKS", > which you would create/extend to cover that bad PE, > so that won't be re-allocated again later: > lvextend VG/BAD_BLOCKS -l +1 /dev/broken:PE > > Better yet, pvchange -an /dev/broken, > so it won't be used for new LVs anymore, > and pvmove /dev/broken completely to somewhere else. > > So much for the theory, how I would try to do this. > In case I would do this at all. > Which I probably won't, if I had an other PV available. > > ;-) > > I'm unsure how pvmove will handle IO errors, though. > > > > But I'd strongly recommend to get rid of such broken driver quickly then > > > you loose any more data - IMHO it's the most efficient solution cost & > > > time. > > Right. > > Lars _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
