Reconfiguring one SW-RAID when other RAIDs are running

Reconfiguring one SW-RAID when other RAIDs are running

[H. Peter Anvin]

Hi all,

I'm trying to re-create a RAID while leaving the other RAIDs -- 
including the root filesystem -- running, but mkraid refuses to run:

hera 1 # mkraid /dev/md2
/dev/md0: array is active -- run raidstop first.
mkraid: aborted.
(In addition to the above messages, see the syslog and /proc/mdstat as well
  for potential clues.)

hera 2 # cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid5] [multipath]
read_ahead 1024 sectors
md1 : active raid5 sdf2[5] sdc2[4] sde2[2] sdd2[3] sdb2[1] sda2[0]
       50339328 blocks level 5, 64k chunk, algorithm 0 [4/4] [UUUU]

md0 : active raid5 sdf3[5] sdc3[4] sde3[2] sdd3[3] sdb3[1] sda3[0]
       298881024 blocks level 5, 64k chunk, algorithm 0 [4/4] [UUUU]

unused devices: <none>


(And no, there is no overlap between them.)

Anyone know how to work around this problem?  This is using 
raidtools-1.00.2-1.3 from RedHat, which seems to be just 
raidtools-1.00.2.tar.gz.

(Also note: the raid directory on kernel.org seems to be abandoned. 
Unless someone speaks up I'm going to remove it.)

	-hpa

Re: Reconfiguring one SW-RAID when other RAIDs are running

[Neil Brown]

On Monday November 4, hpa@zytor.com wrote:
> Hi all,
> 
> I'm trying to re-create a RAID while leaving the other RAIDs -- 
> including the root filesystem -- running, but mkraid refuses to run:
> 
> hera 1 # mkraid /dev/md2
> /dev/md0: array is active -- run raidstop first.
> mkraid: aborted.
> (In addition to the above messages, see the syslog and /proc/mdstat as well
>   for potential clues.)

I cannot offer any help on using mkraid, except to avoid it :-(
mdadm is (I believe and others agree) much easier to use.
  http://www.cse.unsw.edu.au/~neilb/source/mdadm/

It is definately being maintained, not that it has needed much...

> 
> (Also note: the raid directory on kernel.org seems to be abandoned. 
> Unless someone speaks up I'm going to remove it.)
> 

Again, I cannot comment on this directory, but would there be any
change of getting somewhere on kernel.org to distribute mdadm??

Thanks,
NeilBrown

Re: Reconfiguring one SW-RAID when other RAIDs are running

[H. Peter Anvin]

Neil Brown wrote:
> On Monday November 4, hpa@zytor.com wrote:
> 
>>Hi all,
>>
>>I'm trying to re-create a RAID while leaving the other RAIDs -- 
>>including the root filesystem -- running, but mkraid refuses to run:
>>
>>hera 1 # mkraid /dev/md2
>>/dev/md0: array is active -- run raidstop first.
>>mkraid: aborted.
>>(In addition to the above messages, see the syslog and /proc/mdstat as well
>>  for potential clues.)
> 
> 
> I cannot offer any help on using mkraid, except to avoid it :-(
> mdadm is (I believe and others agree) much easier to use.
>   http://www.cse.unsw.edu.au/~neilb/source/mdadm/
> 
> It is definately being maintained, not that it has needed much...
> 

I actually ended up using mdadm... I actually dislike it not using the 
raidtab file at least as an option; I find the raidtab file to be good 
documentation for what one had done.   I would prefer for mkraid to get 
fixed, if it hasn't already.

> 
>>(Also note: the raid directory on kernel.org seems to be abandoned. 
>>Unless someone speaks up I'm going to remove it.)
>>
> 
> 
> Again, I cannot comment on this directory, but would there be any
> change of getting somewhere on kernel.org to distribute mdadm??
> 

Absolutely... send a GPG key to ftpadmin@kernel.org.

	-hpa

Re: Reconfiguring one SW-RAID when other RAIDs are running

[Joel Becker]

On Tue, Nov 05, 2002 at 02:51:29AM -0800, H. Peter Anvin wrote:
> I actually ended up using mdadm... I actually dislike it not using the 
> raidtab file at least as an option; I find the raidtab file to be good 
> documentation for what one had done.

	Well, lsraid -R can give you the raidtab back from an mdadm
created array.  This can be nice and easy documentation.  In fact,
there's no reason a boot script can't run
'lsraid -R -p > /etc/raidtab.boot'

Joel

-- 

"We will have to repent in this generation not merely for the
 vitriolic words and actions of the bad people, but for the 
 appalling silence of the good people."
	- Rev. Dr. Martin Luther King, Jr.

Joel Becker
Senior Member of Technical Staff
Oracle Corporation
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127

Re: Reconfiguring one SW-RAID when other RAIDs are running

[H. Peter Anvin]

Joel Becker wrote:
> On Tue, Nov 05, 2002 at 02:51:29AM -0800, H. Peter Anvin wrote:
> 
>>I actually ended up using mdadm... I actually dislike it not using the 
>>raidtab file at least as an option; I find the raidtab file to be good 
>>documentation for what one had done.
> 
> 
> 	Well, lsraid -R can give you the raidtab back from an mdadm
> created array.  This can be nice and easy documentation.  In fact,
> there's no reason a boot script can't run
> 'lsraid -R -p > /etc/raidtab.boot'
> 

That's nice, but I still like to be able to use the "edit raidtab then
mkraid", mostly because I think I'm less likely to screw up that way.

	-hpa

Re: Reconfiguring one SW-RAID when other RAIDs are running

[Neil Brown]

On Monday November 4, hpa@zytor.com wrote:
> Hi all,
> 
> I'm trying to re-create a RAID while leaving the other RAIDs -- 
> including the root filesystem -- running, but mkraid refuses to run:
> 
> hera 1 # mkraid /dev/md2
> /dev/md0: array is active -- run raidstop first.
> mkraid: aborted.
> (In addition to the above messages, see the syslog and /proc/mdstat as well
>   for potential clues.)

My guess is that the following patch would fix it, but I haven't
tested it.

NeilBrown

--- mkraid.c	2002/11/05 19:34:57	1.1
+++ mkraid.c	2002/11/05 19:35:29
@@ -244,7 +244,7 @@ int main (int argc, char *argv[])
     while (*args) {
 	for (p = cfg_head; p; p = p->next) {
 	    if (strcmp(p->md_name, *args)) continue;
-	    if (check_active(cfg)) 
+	    if (check_active(p)) 
 		goto abort;
 	    if (force_flag) {
 		fprintf(stderr, "DESTROYING the contents of %s in 5 seconds, Ctrl-C if unsure!\n", *args);