Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-07 Thread Mikulas Patocka
On Fri, 6 Nov 2015, Sami Tolvanen wrote: > On Fri, Nov 06, 2015 at 10:05:24PM +0100, Zdenek Kabelac wrote: > > So how do you want to correctly 'restore' missing full sectors > > with just 0.8% data overhead ?? > > We use interleaving. Each byte in a 4k block is part of a different >

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-07 Thread Mikulas Patocka
On Fri, 6 Nov 2015, Sami Tolvanen wrote: > On Fri, Nov 06, 2015 at 08:20:15PM +0100, Zdenek Kabelac wrote: > > i.e. you have 1G of space - you want to give 250MB as 'redundancy' - > > so create 4 partition > > We cannot afford to set aside 25% of read-only partition space for You can have

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-07 Thread Mikulas Patocka
On Fri, 6 Nov 2015, Sami Tolvanen wrote: > On Fri, Nov 06, 2015 at 08:20:15PM +0100, Zdenek Kabelac wrote: > > i.e. you have 1G of space - you want to give 250MB as 'redundancy' - > > so create 4 partition > > We cannot afford to set aside 25% of read-only partition space for You can have

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-07 Thread Mikulas Patocka
On Fri, 6 Nov 2015, Sami Tolvanen wrote: > On Fri, Nov 06, 2015 at 10:05:24PM +0100, Zdenek Kabelac wrote: > > So how do you want to correctly 'restore' missing full sectors > > with just 0.8% data overhead ?? > > We use interleaving. Each byte in a 4k block is part of a different >

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-06 Thread Sami Tolvanen
On Fri, Nov 06, 2015 at 10:05:24PM +0100, Zdenek Kabelac wrote: > So how do you want to correctly 'restore' missing full sectors > with just 0.8% data overhead ?? We use interleaving. Each byte in a 4k block is part of a different Reed-Solomon block, which means an entire lost 4k data block

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-06 Thread Zdenek Kabelac
Dne 6.11.2015 v 21:27 Sami Tolvanen napsal(a): On Fri, Nov 06, 2015 at 08:20:15PM +0100, Zdenek Kabelac wrote: i.e. you have 1G of space - you want to give 250MB as 'redundancy' - so create 4 partition well data safety has it's price - user should choose what he prefers - more games and

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-06 Thread Sami Tolvanen
On Fri, Nov 06, 2015 at 08:20:15PM +0100, Zdenek Kabelac wrote: > i.e. you have 1G of space - you want to give 250MB as 'redundancy' - > so create 4 partition We cannot afford to set aside 25% of read-only partition space for redundancy on mobile devices, and would rather not impact

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-06 Thread Zdenek Kabelac
Dne 6.11.2015 v 20:06 Sami Tolvanen napsal(a): On Fri, Nov 06, 2015 at 12:23:29PM -0500, Mikulas Patocka wrote: I'm also wondering what is this patch useful for. Disks and flash controllers have their own error detection and correction I think I addressed this earlier. Some storage devices

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-06 Thread Zdenek Kabelac
Dne 6.11.2015 v 20:06 Sami Tolvanen napsal(a): On Fri, Nov 06, 2015 at 12:23:29PM -0500, Mikulas Patocka wrote: I'm also wondering what is this patch useful for. Disks and flash controllers have their own error detection and correction I think I addressed this earlier. Some storage devices

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-06 Thread Sami Tolvanen
On Fri, Nov 06, 2015 at 08:20:15PM +0100, Zdenek Kabelac wrote: > i.e. you have 1G of space - you want to give 250MB as 'redundancy' - > so create 4 partition We cannot afford to set aside 25% of read-only partition space for redundancy on mobile devices, and would rather not impact

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-06 Thread Zdenek Kabelac
Dne 6.11.2015 v 21:27 Sami Tolvanen napsal(a): On Fri, Nov 06, 2015 at 08:20:15PM +0100, Zdenek Kabelac wrote: i.e. you have 1G of space - you want to give 250MB as 'redundancy' - so create 4 partition well data safety has it's price - user should choose what he prefers - more games and

Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

2015-11-06 Thread Sami Tolvanen
On Fri, Nov 06, 2015 at 10:05:24PM +0100, Zdenek Kabelac wrote: > So how do you want to correctly 'restore' missing full sectors > with just 0.8% data overhead ?? We use interleaving. Each byte in a 4k block is part of a different Reed-Solomon block, which means an entire lost 4k data block