mdadm --dangerous-no-resync equivalent

mdadm --dangerous-no-resync equivalent

[flame]

Hi,

I have an installer (http://sourceforge.net/projects/terraformix/) that
creates Raid 1 arrays, previously the arrays were created with mkraid
using the --dangerous-no-resync option. I am now required to build the
arrays with mdadm and have the following questions ;

1) Is there an equivalent of --dangerous-no-resync in mdadm ?

2) Can I just go ahead and install onto a newly created RAID 1 array
without waiting for it to resync ?

3) Can I just go ahead and install onto a newly created RAID 5 array
without waiting for it to resync ?

Thanks in advance.

-- 
flame <flame@ivt.com.au>

Re: mdadm --dangerous-no-resync equivalent

[Neil Brown]

On Thursday March 10, flame@ivt.com.au wrote:
> Hi,
> 
> I have an installer (http://sourceforge.net/projects/terraformix/) that
> creates Raid 1 arrays, previously the arrays were created with mkraid
> using the --dangerous-no-resync option. I am now required to build the
> arrays with mdadm and have the following questions ;
> 
> 1) Is there an equivalent of --dangerous-no-resync in mdadm ?

No, though there might be one day, in which case it would be
     --assume-clean
(which works with --build, but is currently ignored for --create).

> 
> 2) Can I just go ahead and install onto a newly created RAID 1 array
> without waiting for it to resync ?

Yes.

> 
> 3) Can I just go ahead and install onto a newly created RAID 5 array
> without waiting for it to resync ?

Yes.


> 
> Thanks in advance.

You're welcome.

NeilBrown

Re: mdadm --dangerous-no-resync equivalent

[Daniel Pittman]

On 10 Mar 2005, flame@ivt.com.au wrote:
> Hi,
>
> I have an installer (http://sourceforge.net/projects/terraformix/) that
> creates Raid 1 arrays, previously the arrays were created with mkraid
> using the --dangerous-no-resync option. I am now required to build the
> arrays with mdadm and have the following questions ;
>
> 1) Is there an equivalent of --dangerous-no-resync in mdadm ?
>
> 2) Can I just go ahead and install onto a newly created RAID 1 array
> without waiting for it to resync ?

Yes.

> 3) Can I just go ahead and install onto a newly created RAID 5 array
> without waiting for it to resync ?

Yes.

Also, you can happily reboot while the resync is no progress with the
full expectation that it will work correctly -- assemble, then take up
the resync process again -- when your machine restarts.

I have had no problems with this at all, despite doing a large number of
installs onto both of those RAID levels.

Also, the Debian installer for testing/unstable makes the assumption
that this will "just work" in the RAID component -- at least, in so far
as not taking any special care to avoid rebooting during the resync
process.

Regards,
        Daniel
-- 
A large number of installed systems work by fiat.
That is, they work by being declared to work.
        -- Anatol Holt