auto start raid0 with no superblock?

auto start raid0 with no superblock?

[Thomas Fjellstrom]

I'm testing out accessing a "Windows DynamicDisk Raid0" array under linux, and 
for the most part it works very well. My only problem is mdadm will not auto 
start the array even when I have it setup in mdadm.conf (mdadm is told to auto 
start all arrays found there). Basically I have to manually run "mdadm --build 
/dev/md0 --chunk=64 --level=raid0 --raid-devices=4 /dev/sdc1 /dev/sdd1 
/dev/sde1 /dev/sdf1" then "mount /mnt/winraid" when I want to access the 
filesystem (using ntfs-3g if anyone was wondering).

All I get from mdadm/syslog is this:
Aug  4 02:43:10 natasha kernel: [    7.862373] md: md0 stopped.                                                                                                                           
Aug  4 02:43:18 natasha mdadm[3597]: DeviceDisappeared event detected on md 
device /dev/md0

The reason I'm trying to use non persistent superblocks is I'm assuming trying 
to save them will damage the windows DynamicDisk metadata in some way.

-- 
Thomas Fjellstrom
tfjellstrom@shaw.ca

Re: auto start raid0 with no superblock?

[NeilBrown]

On Wed, August 5, 2009 6:44 am, Thomas Fjellstrom wrote:
> I'm testing out accessing a "Windows DynamicDisk Raid0" array under linux,
> and
> for the most part it works very well. My only problem is mdadm will not
> auto
> start the array even when I have it setup in mdadm.conf (mdadm is told to
> auto
> start all arrays found there). Basically I have to manually run "mdadm
> --build
> /dev/md0 --chunk=64 --level=raid0 --raid-devices=4 /dev/sdc1 /dev/sdd1
> /dev/sde1 /dev/sdf1" then "mount /mnt/winraid" when I want to access the
> filesystem (using ntfs-3g if anyone was wondering).

Of course you don't have to run it manually.  You can put it in
a script in /etc/rc5.d/Sxxwhatever

That is in fact the recommended way of doing this.  There is really
nothing that mdadm can do for you to make this any easier, so it
doesn't bother.

>
> All I get from mdadm/syslog is this:
> Aug  4 02:43:10 natasha kernel: [    7.862373] md: md0 stopped.
> Aug  4 02:43:18 natasha mdadm[3597]: DeviceDisappeared event detected on
> md
> device /dev/md0
>
> The reason I'm trying to use non persistent superblocks is I'm assuming
> trying
> to save them will damage the windows DynamicDisk metadata in some way.

Sounds very sensible.

NeilBrown

Re: auto start raid0 with no superblock?

[John Robinson]

On 04/08/2009 23:35, NeilBrown wrote:
> On Wed, August 5, 2009 6:44 am, Thomas Fjellstrom wrote:
>> I'm testing out accessing a "Windows DynamicDisk Raid0" array under linux,
>> and
>> for the most part it works very well. My only problem is mdadm will not
>> auto
>> start the array even when I have it setup in mdadm.conf (mdadm is told to
>> auto
>> start all arrays found there). Basically I have to manually run "mdadm
>> --build
>> /dev/md0 --chunk=64 --level=raid0 --raid-devices=4 /dev/sdc1 /dev/sdd1
>> /dev/sde1 /dev/sdf1" then "mount /mnt/winraid" when I want to access the
>> filesystem (using ntfs-3g if anyone was wondering).
> 
> Of course you don't have to run it manually.  You can put it in
> a script in /etc/rc5.d/Sxxwhatever
> 
> That is in fact the recommended way of doing this.  There is really
> nothing that mdadm can do for you to make this any easier, so it
> doesn't bother.

It doesn't, and couldn't, support
   ARRAY /dev/md0 devices=/dev/sdc1,/dev/sdd1,/dev/sde1,/dev/sdf1 
level=0 metadata=none
appearing in mdadm.conf?

Cheers,

John.