Linear RAID hot grow

Linear RAID hot grow

[Dat Chu]

I am trying to find the mdadm version that support Linear RAID hot
grow. Does anyone have a link to point me to? I am currently running
2.6.2.

With warm regards,
Dat Chu

Re: Linear RAID hot grow

[Justin Piszcz]

On Mon, 20 Aug 2007, Dat Chu wrote:

> I am trying to find the mdadm version that support Linear RAID hot
> grow. Does anyone have a link to point me to? I am currently running
> 2.6.2.
>
> With warm regards,
> Dat Chu
> -
> 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
>

Not sure, it seems like it would be supported by now?

But according to the docs for 2.6.2:

        Grow   Grow  (or shrink) an array, or otherwise reshape it in some way.
               Currently supported growth options including changing the active
               size of component devices in RAID level 1/4/5/6 and changing the
               number of active devices in RAID1/5/6.

--

http://neil.brown.name/blog/SoftRaid

--grow option for "linear" md arrays

I've just been working on an enhancement for Linux "MD" linear arrays 
which allows them to be enlanged.

More specifically, a new device (typcially disk drive) can be added to the 
end of an active linear array now. The size increases accordingly.

You can find patches for mdadm and 2.6.7-rc3-mm1.

It is still a work in progress, as it isn't documented, some of the code 
doesn't report errors very nicely, and I realised that there is some work 
needed in md.c with respect to handling new superblocks.

I really should do the new-superblock code in mdadm and get it all tidied 
up.

Re: Linear RAID hot grow

[Dat Chu]

The links on Neil's website to those patches are no longer there. When
I try to hot grow a linear raid, it says that hot grow for linear raid
is not supported.

Where would I find those patches?

With warm regards,
Dat Chu



>
>
>
> On 8/20/07, Justin Piszcz <jpiszcz@lucidpixels.com> wrote:
> >
> >
> > On Mon, 20 Aug 2007, Dat Chu wrote:
> >
> > > I am trying to find the mdadm version that support Linear RAID hot
> > > grow. Does anyone have a link to point me to? I am currently running
> > > 2.6.2.
> > >
> > > With warm regards,
> > > Dat Chu
> > > -
> > > 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
> > >
> >
> > Not sure, it seems like it would be supported by now?
> >
> > But according to the docs for 2.6.2:
> >
> >         Grow   Grow  (or shrink) an array, or otherwise reshape it in some way.
> >                Currently supported growth options including changing the active
> >                size of component devices in RAID level 1/4/5/6 and changing the
> >                number of active devices in RAID1/5/6.
> >
> > --
> >
> > http://neil.brown.name/blog/SoftRaid
> >
> > --grow option for "linear" md arrays
> >
> >  I've just been working on an enhancement for Linux "MD" linear arrays
> > which allows them to be enlanged.
> >
> > More specifically, a new device (typcially disk drive) can be added to the
> > end of an active linear array now. The size increases accordingly.
> >
> > You can find patches for mdadm and 2.6.7-rc3-mm1.
> >
> > It is still a work in progress, as it isn't documented, some of the code
> > doesn't report errors very nicely, and I realised that there is some work
> > needed in md.c with respect to handling new superblocks.
> >
> > I really should do the new-superblock code in mdadm and get it all tidied
> > up.
> >
>
>

Re: Linear RAID hot grow

[Neil Brown]

On Monday August 20, dattanchu@gmail.com wrote:
> The links on Neil's website to those patches are no longer there. When
> I try to hot grow a linear raid, it says that hot grow for linear raid
> is not supported.

What is the exact error message?
What kernel are you using?

hot-grow for linear does work with recent kernels and mdadm - it is
part of my test suite.
  mdadm --grow /dev/md-linear --add /dev/new-device

NeilBrown

Re: Linear RAID hot grow

[Dat Chu]

I am currently running 2.6.22.1 kernel with mdadm version 2.6.2.

When I try to run
mdadm --grow /dev/md2 --add /dev/sdd1
mdadm: Cannot add new disk to this array

mdadm -D /dev/md2
/dev/md2:
        Version : 00.90.03
  Creation Time : Thu Apr 12 15:10:30 2007
     Raid Level : linear
     Array Size : 4394524224 (4190.94 GiB 4499.99 GB)
   Raid Devices : 3
  Total Devices : 3
Preferred Minor : 2
    Persistence : Superblock is persistent

    Update Time : Mon Aug 20 21:59:02 2007
          State : active
 Active Devices : 3
Working Devices : 3
 Failed Devices : 0
  Spare Devices : 0

       Rounding : 64K

           UUID : 2d55a746:46480234:2bd67da3:078a1f37
         Events : 0.17

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       8       17        1      active sync   /dev/sdb1
       2       8       33        2      active sync   /dev/sdc1

I am missing something?

Thanks for the quick reply Neil.

With warm regards,
Dat Chu

On 8/20/07, Neil Brown <neilb@suse.de> wrote:
> On Monday August 20, dattanchu@gmail.com wrote:
> > The links on Neil's website to those patches are no longer there. When
> > I try to hot grow a linear raid, it says that hot grow for linear raid
> > is not supported.
>
> What is the exact error message?
> What kernel are you using?
>
> hot-grow for linear does work with recent kernels and mdadm - it is
> part of my test suite.
>   mdadm --grow /dev/md-linear --add /dev/new-device
>
> NeilBrown
>

Re: Linear RAID hot grow

[Neil Brown]

On Monday August 20, dattanchu@gmail.com wrote:
> I am currently running 2.6.22.1 kernel with mdadm version 2.6.2.

That combination should work.

> 
> When I try to run
> mdadm --grow /dev/md2 --add /dev/sdd1
> mdadm: Cannot add new disk to this array

Odd.  I tried add a drive to a three-drive linear array and it
worked, though my drives are somewhat smaller than yours - that
shouldn't matter though.

Do you get any kernel messages at the time when you try to add?
  dmesg | tail -20

NeilBrown

Re: Linear RAID hot grow

[Dat Chu]

md: sdd1 has invalid sb, not importing!
md: md_import_device returned -22

That is what I get for running dmesg | tail -20

Here is the relevant stanza from fdisk -l

Disk /dev/sda: 1649.2 GB, 1649267441664 bytes
255 heads, 63 sectors/track, 200512 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1      200512  1610612608+  83  Linux

Disk /dev/sdb: 1638.2 GB, 1638272335872 bytes
255 heads, 63 sectors/track, 199175 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1      199175  1599873156   83  Linux

Disk /dev/sdc: 1212.4 GB, 1212459515904 bytes
255 heads, 63 sectors/track, 147406 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1      147406  1184038663+  83  Linux

Disk /dev/sdd: 1124.9 GB, 1124999233536 bytes
255 heads, 63 sectors/track, 136773 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1      136773  1098629091   83  Linux

Disk /dev/sde: 1124.9 GB, 1124999233536 bytes
255 heads, 63 sectors/track, 136773 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sde1               1      136773  1098629091   83  Linux


On 8/21/07, Neil Brown <neilb@suse.de> wrote:
> On Monday August 20, dattanchu@gmail.com wrote:
> > I am currently running 2.6.22.1 kernel with mdadm version 2.6.2.
>
> That combination should work.
>
> >
> > When I try to run
> > mdadm --grow /dev/md2 --add /dev/sdd1
> > mdadm: Cannot add new disk to this array
>
> Odd.  I tried add a drive to a three-drive linear array and it
> worked, though my drives are somewhat smaller than yours - that
> shouldn't matter though.
>
> Do you get any kernel messages at the time when you try to add?
>   dmesg | tail -20
>
> NeilBrown
>