RAID detection and activation w/o auto detection

RAID detection and activation w/o auto detection

[bo]

Hello,

How to detect and activate the RAID manually without 
"auto detection"(0xFD in partition type)?

I tried with "mdadm -R" or "mdadm -A", but it did not work.

Thanks in advance,

Bo

Re: RAID detection and activation w/o auto detection

[Neil Brown]

On Monday April 29, bo@sosnetwork.net wrote:
> Hello,
> 
> How to detect and activate the RAID manually without 
> "auto detection"(0xFD in partition type)?
> 
> I tried with "mdadm -R" or "mdadm -A", but it did not work.

echo '/dev/hd* /dev/sd*' > /etc/mdadm.conf
mdadm -Dsb >> /etc/mdadm.conf

# look at /etc/mdadm.conf and make sure that it looks ok.

# add  "mdadm -As" to an appropriate startup script.

Note that this won't work for assembling the root filesystem.
To do that, you either need an init-ramdisk which runs "mdadm -As", or
use kernel parameters to start the root device.e.g.

  append="root=/dev/md0 md=0,/dev/hda1,/dev/hdc1"

NeilBrown

Re: RAID detection and activation w/o auto detection

[Mr. James W. Laferriere]

	Hello Neil ,  An suggestion for -D function of mdadm
	please allow use of  '-c/--config='  ?

	I tried the suggestion below .  But I did not want to overwrite
	the /etc version of mdadm.conf , cause it works .  So I tried to
	use the -c option & mdadm replies with the below .  Tia ,  JimL

~# mdadm -V
mdadm - v0.8.2 - 11 April 2002

~# echo '/dev/hd* /dev/sd*' > ./mdadm.conf

~# mdadm -Dsb -c ./mdadm.conf >> ./mdadm.conf
mdadm: option c not valid in misc mode

~# mdadm -Dsb --config=./mdadm.conf >> ./mdadm.conf
mdadm: option c not valid in misc mode


On Tue, 30 Apr 2002, Neil Brown wrote:

> On Monday April 29, bo@sosnetwork.net wrote:
> > Hello,
> >
> > How to detect and activate the RAID manually without
> > "auto detection"(0xFD in partition type)?
> >
> > I tried with "mdadm -R" or "mdadm -A", but it did not work.
>
> echo '/dev/hd* /dev/sd*' > /etc/mdadm.conf
> mdadm -Dsb >> /etc/mdadm.conf
>
> # look at /etc/mdadm.conf and make sure that it looks ok.
>
> # add  "mdadm -As" to an appropriate startup script.
>
> Note that this won't work for assembling the root filesystem.
> To do that, you either need an init-ramdisk which runs "mdadm -As", or
> use kernel parameters to start the root device.e.g.
>
>   append="root=/dev/md0 md=0,/dev/hda1,/dev/hdc1"
>
> 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
>

       +------------------------------------------------------------------+
       | James   W.   Laferriere | System    Techniques | Give me VMS     |
       | Network        Engineer |     P.O. Box 854     |  Give me Linux  |
       | babydr@baby-dragons.com | Coudersport PA 16915 |   only  on  AXP |
       +------------------------------------------------------------------+

Re: RAID detection and activation w/o auto detection

[Mr. James W. Laferriere]

	Hello Neil ,  OK mia culpa .  But I don't see what good the echo
	below does for us then ,  as in ...

~# more ./mdadm.conf
/dev/hd* /dev/sd*
ARRAY /dev/md0 level=raid5 num-devices=3 UUID=b285b144:ae0b561b:b5b55686:ed216a4c

	Without the DEVICE in front of '/dev/hd* /dev/sd*' they are
	meaningless .  Right ?  Tia ,  JimL

On Tue, 30 Apr 2002, Mr. James W. Laferriere wrote:
> 	Hello Neil ,  An suggestion for -D function of mdadm
> 	please allow use of  '-c/--config='  ?
> 	I tried the suggestion below .  But I did not want to overwrite
> 	the /etc version of mdadm.conf , cause it works .  So I tried to
> 	use the -c option & mdadm replies with the below .  Tia ,  JimL
> ~# mdadm -V
> mdadm - v0.8.2 - 11 April 2002
> ~# echo '/dev/hd* /dev/sd*' > ./mdadm.conf
> ~# mdadm -Dsb -c ./mdadm.conf >> ./mdadm.conf
> mdadm: option c not valid in misc mode
> ~# mdadm -Dsb --config=./mdadm.conf >> ./mdadm.conf
> mdadm: option c not valid in misc mode

> On Tue, 30 Apr 2002, Neil Brown wrote:
> > On Monday April 29, bo@sosnetwork.net wrote:
> > > Hello,
> > > How to detect and activate the RAID manually without
> > > "auto detection"(0xFD in partition type)?
> > > I tried with "mdadm -R" or "mdadm -A", but it did not work.
> >
> > echo '/dev/hd* /dev/sd*' > /etc/mdadm.conf
> > mdadm -Dsb >> /etc/mdadm.conf
> >
> > # look at /etc/mdadm.conf and make sure that it looks ok.
> >
> > # add  "mdadm -As" to an appropriate startup script.
> >
> > Note that this won't work for assembling the root filesystem.
> > To do that, you either need an init-ramdisk which runs "mdadm -As", or
> > use kernel parameters to start the root device.e.g.
> >
> >   append="root=/dev/md0 md=0,/dev/hda1,/dev/hdc1"
> >
> > NeilBrown

       +------------------------------------------------------------------+
       | James   W.   Laferriere | System    Techniques | Give me VMS     |
       | Network        Engineer |     P.O. Box 854     |  Give me Linux  |
       | babydr@baby-dragons.com | Coudersport PA 16915 |   only  on  AXP |
       +------------------------------------------------------------------+

Re: RAID detection and activation w/o auto detection

[Neil Brown]

On Tuesday April 30, babydr@baby-dragons.com wrote:
> 
> 	Hello Neil ,  OK mia culpa .  But I don't see what good the echo
> 	below does for us then ,  as in ...
> 
> ~# more ./mdadm.conf
> /dev/hd* /dev/sd*
> ARRAY /dev/md0 level=raid5 num-devices=3 UUID=b285b144:ae0b561b:b5b55686:ed216a4c
> 
> 	Without the DEVICE in front of '/dev/hd* /dev/sd*' they are
> 	meaningless .  Right ?  Tia ,  JimL

Yep.  My mistake.  It should have been:

   echo 'DEVICE /dev/hd* /dev/sd*' > /etc/mdadm.conf

As I think you realised, --config is pointless with -Dsb, as it
doesn't read the config file, it reads /proc/mdstat.
However --config would be meaningful with -Esb, and the next release
will allow it.

Thanks,

NeilBrown

RE: RAID detection and activation w/o auto detection

[Yuval Yeret]

Should we consider mdadm as a replacement to raidstart/raidstop ? 

I ask because we are seeing strange behaviour in starting a raid when
one of the paths is not available.

Thank,
Yuval Yeret


-----Original Message-----
From: Neil Brown [mailto:neilb@cse.unsw.edu.au]
Sent: Wednesday, May 01, 2002 7:21 AM
To: Mr. James W. Laferriere
Cc: linux-raid maillist
Subject: Re: RAID detection and activation w/o auto detection 


On Tuesday April 30, babydr@baby-dragons.com wrote:
> 
> 	Hello Neil ,  OK mia culpa .  But I don't see what good the echo
> 	below does for us then ,  as in ...
> 
> ~# more ./mdadm.conf
> /dev/hd* /dev/sd*
> ARRAY /dev/md0 level=raid5 num-devices=3
UUID=b285b144:ae0b561b:b5b55686:ed216a4c
> 
> 	Without the DEVICE in front of '/dev/hd* /dev/sd*' they are
> 	meaningless .  Right ?  Tia ,  JimL

Yep.  My mistake.  It should have been:

   echo 'DEVICE /dev/hd* /dev/sd*' > /etc/mdadm.conf

As I think you realised, --config is pointless with -Dsb, as it
doesn't read the config file, it reads /proc/mdstat.
However --config would be meaningful with -Esb, and the next release
will allow it.

Thanks,

NeilBrown
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RE: RAID detection and activation w/o auto detection

[Neil Brown]

On Wednesday May 1, yuval@exanet.com wrote:
> 
> 
> Should we consider mdadm as a replacement to raidstart/raidstop ? 

I certainly consider mdadm a replacement for raidstart/raidstop.

If you find it works well for you, you might like to do the same.

Or to put it another way:
 I am happy to provide software and advice on how to use it for free.
 I am not comfortable providing advice as to what is best for you to
   do for free.

NeilBrown