Re: Where can i download mdadm 3.3

[NeilBrown <neilb@suse.de>]

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On Tue, 4 Dec 2012 10:59:53 -0300 Salatiel Filho <salatiel.filho@gmail.com>
wrote:

> On Mon, Nov 26, 2012 at 9:13 PM, NeilBrown <neilb@suse.de> wrote:
> > On Sun, 25 Nov 2012 10:30:10 -0300 Salatiel Filho <salatiel.filho@gmail.com>
> > wrote:
> >
> >> On Tue, Nov 20, 2012 at 6:25 PM, NeilBrown <neilb@suse.de> wrote:
> >> >
> >> > On Tue, 20 Nov 2012 14:00:35 -0300 Salatiel Filho <salatiel.filho@gmail.com>
> >> > wrote:
> >> >
> >> > > []'s
> >> > > Salatiel
> >> > >
> >> > >
> >> > > On Tue, Nov 20, 2012 at 8:02 AM, Salatiel Filho
> >> > > <salatiel.filho@gmail.com> wrote:
> >> > > > Thanks Neil !
> >> > > > []'s
> >> > > > Salatiel
> >> > > >
> >> > > >
> >> > > > On Mon, Nov 19, 2012 at 10:26 PM, NeilBrown <neilb@suse.de> wrote:
> >> > > >> On Sun, 18 Nov 2012 10:42:22 -0300 Salatiel Filho <salatiel.filho@gmail.com>
> >> > > >> wrote:
> >> > > >>
> >> > > >>> Hi guys, i will be building a few arrays very soon and i'd like to
> >> > > >>> test the badblock feature and the replaceable feature, but i haven`t
> >> > > >>> found where i can download the source of mdadm 1.3. Where can i get it
> >> > > >>> ?
> >> > > >>>
> >> > > >> You can't.  3.3 doesn't exist yet.
> >> > > >>
> >> > > >> However
> >> > > >>   git clone git://neil.brown.name/mdadm
> >> > > >>   cd mdadm
> >> > > >>   make
> >> > > >>
> >> > > >> will get you code that supports bad blocks and replaceable devices.
> >> > > >>
> >> > > >> Alternately you can get a tar file at
> >> > > >>
> >> > > >>    http://git.neil.brown.name/git?p=mdadm.git;a=snapshot;h=master
> >> > > >>
> >> > > >> NeilBrown
> >> > >
> >> > > Forgot to send a copy to the list:
> >> > >
> >> > >
> >> > > Now the question, how do i enable badblock list ?
> >> > > # mdadm -A /dev/md1 /dev/sd[bcd]2 --update=bbl  ?
> >> >
> >> > Yes, I think that is right - does it work?
> >> >
> >> > >
> >> > > I actually created also a new array
> >> > > # mdadm -C -n4 -l5 -e 1.2 /dev/md2 /dev/sd[bcde]3 ,
> >> > > but how do i verify if badblock support was enabled ?
> >> >
> >> > mdadm -E /dev/sdb3
> >> >
> >> > should show
> >> >
> >> >    Bad Block Log : 512 entries available at offset xxx sectors
> >> >
> >> > NeilBrown
> >> >
> >> > > --
> >> > > To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> >> > > the body of a message to majordomo@vger.kernel.org
> >> > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >> >
> >>
> >>
> >> Well, about the tests:
> >> I have put some data on a degraded raid 5 with 3 disks where one of
> >> them has random read errors. After that i added a new disk and the
> >> raid started to resync.
> >> After 62.5% i started getting read errors on /dev/sdd2 and the array
> >> stopped to resync.
> >
> > Any useful messages from the kernel log?
> >
> >>
> >> 1) Shouldn`t badblocks be ignored to allow the recover of most data?
> >> I can see in mdadm -E /dev/sdd2   Bad Block Log : 512 entries
> >> available at offset 262128 sectors - bad blocks present.
> >
> > That's the theory.  And bad blocks found should be recorded on both sdd2 and
> > the new device.
> >
> >>
> >> 2) After stop the array and try to reassembled with   mdadm -A
> >> /dev/md1 /dev/sd[bcde]2 --force i got the following message:
> >> mdadm -A /dev/md1 /dev/sd[bcde]2 --force
> >> mdadm: forcing event count in /dev/sdb2(0) from 87705 upto 87713
> >> mdadm: forcing event count in /dev/sdc2(1) from 87705 upto 87713
> >> mdadm: /dev/md1 has been started with 3 drives (out of 4).
> >
> > That doesn't look good.  Again, complete kernel messages might help.
> >
> >>
> >> and i noticed that sde2 was not added to the array.
> >>
> >> # mdadm -D /dev/md1
> >> /dev/md1:
> >>         Version : 1.2
> >>   Creation Time : Tue Nov 20 08:43:35 2012
> >>      Raid Level : raid5
> >>      Array Size : 3918320640 (3736.80 GiB 4012.36 GB)
> >>   Used Dev Size : 1306106880 (1245.60 GiB 1337.45 GB)
> >>    Raid Devices : 4
> >>   Total Devices : 3
> >>     Persistence : Superblock is persistent
> >>
> >>   Intent Bitmap : Internal
> >>
> >>     Update Time : Sun Nov 25 10:04:06 2012
> >>           State : active, degraded
> >>  Active Devices : 3
> >> Working Devices : 3
> >>  Failed Devices : 0
> >>   Spare Devices : 0
> >>
> >>          Layout : left-symmetric
> >>      Chunk Size : 512K
> >>
> >>            Name : zotac:1  (local to host zotac)
> >>            UUID : 93e55a39:94681b9d:4c0a1a15:cad51a71
> >>          Events : 87713
> >>
> >>     Number   Major   Minor   RaidDevice State
> >>        0       8       18        0      active sync   /dev/sdb2
> >>        1       8       34        1      active sync   /dev/sdc2
> >>        2       8       50        2      active sync   /dev/sdd2
> >>        6       0        0        6      removed
> >>
> >>
> >> After add it manually , mdadm -a /dev/md1 /dev/sde2
> >> the rebuild started from the beginning, ignoring the recovery offset:
> >
> > That would be because the 'Events' number is too old so the 'recovery offset'
> > is suspect.
> >
> >
> >>
> >> # mdadm -E /dev/sde2
> >> /dev/sde2:
> >>           Magic : a92b4efc
> >>         Version : 1.2
> >>     Feature Map : 0xb
> >>      Array UUID : 93e55a39:94681b9d:4c0a1a15:cad51a71
> >>            Name : zotac:1  (local to host zotac)
> >>   Creation Time : Tue Nov 20 08:43:35 2012
> >>      Raid Level : raid5
> >>    Raid Devices : 4
> >>
> >>  Avail Dev Size : 3592190757 (1712.89 GiB 1839.20 GB)
> >>      Array Size : 3918320640 (3736.80 GiB 4012.36 GB)
> >>   Used Dev Size : 2612213760 (1245.60 GiB 1337.45 GB)
> >>     Data Offset : 262144 sectors
> >>    Super Offset : 8 sectors
> >> Recovery Offset : 1634547480 sectors
> >>           State : clean
> >>     Device UUID : 08019409:984c2217:21706201:039b6bbf
> >>
> >> Internal Bitmap : 8 sectors from superblock
> >>     Update Time : Sun Nov 25 10:04:06 2012
> >>   Bad Block Log : 512 entries available at offset 262128 sectors
> >>        Checksum : bd6c4947 - correct
> >>          Events : 87705
> >>
> >>          Layout : left-symmetric
> >>      Chunk Size : 512K
> >>
> >>    Device Role : Active device 3
> >>    Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
> >>
> >>
> >>
> >> 3) What's the correct procedure that allows me recover most of the
> >> data, ignoring the readerrors ?
> >>
> >> 4) I know that sdd2 has read errors at  sectors 1634863440 -
> >> 1634863800, if i write zero directly to those sectors using 'dd' , how
> >> will raid behave during rebuild? After a write it will probably be
> >> able to read it again (i dont care about the data on those sectors) .
> >
> > If it can read, it will, and will write to the new device.
> >
> >>
> >> 5) Right now i am not using replaceable option , but where replaceable
> >> option could help me here ?
> >
> > I don't think 'replaceable' is particularly relevant here.
> >
> > NeilBrown
> >
> >
> >>
> >>
> >> Thanks !
> >
> 
> I am still doing some tests and i will report back.
> btw, is there anyway to see how many badblock the disk has ? I can see
> only the 'bad blocks present.' , but not how many.

When the array is active you can look in /sys/block/mdXX/md/dev-YYY/badblocks
It will list them all.
Currently mdadm doesn't extract this information.  I should probably add an
   --examine-badblocks
option to list them.

NeilBrown

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