disable creation of md127

disable creation of md127

[Patrick H.]

How can I prevent the MD driver from auto-creating md127 on boot?
I have a server which is exporting /dev/sdb1 via iSCSI. The remote 
client for this device is using it in a raid device so it has raid 
metadata on it. However because of this, when the target server boots 
up, the md driver shoves it into md127. And because of this, the iSCSI 
target daemon (tgtd) wont export the device as its now part of a raid 
device.
The partition type is 0x83, not 0xfd.

RHEL6 2.6.32-71

-Patrick

Re: disable creation of md127

[Neil Brown]

On Fri, 10 Dec 2010 14:38:30 -0700 "Patrick H." <linux-raid@feystorm.net>
wrote:

> How can I prevent the MD driver from auto-creating md127 on boot?
> I have a server which is exporting /dev/sdb1 via iSCSI. The remote 
> client for this device is using it in a raid device so it has raid 
> metadata on it. However because of this, when the target server boots 
> up, the md driver shoves it into md127. And because of this, the iSCSI 
> target daemon (tgtd) wont export the device as its now part of a raid 
> device.
> The partition type is 0x83, not 0xfd.
> 
> RHEL6 2.6.32-71

The md driver isn't auto-creating this.  
mdadm is being run and being asked to create this, possibly implicitly.

Exactly how you stop this from happening depends on where it is an initrd
script or a boot script that is doing it, and which version of mdadm you have.

If you have 3.0 or later, then putting
   AUTO -all

in mdadm.conf might be enough.
If you have a 2.x, you probably need to tell the init script not to run
mdadm, maybe edit the script, maybe set some default variable.  I know little
about RHEL and so cannot suggest specifics.

NeilBrown

Re: disable creation of md127

[Patrick H.]

Sent: Fri Dec 10 2010 14:58:59 GMT-0700 (Mountain Standard Time)
From: Neil Brown <neilb@suse.de>
To: Patrick H. <linux-raid@feystorm.net> linux-raid@vger.kernel.org
Subject: Re: disable creation of md127
> On Fri, 10 Dec 2010 14:38:30 -0700 "Patrick H." <linux-raid@feystorm.net>
> wrote:
>
>   
>> How can I prevent the MD driver from auto-creating md127 on boot?
>> I have a server which is exporting /dev/sdb1 via iSCSI. The remote 
>> client for this device is using it in a raid device so it has raid 
>> metadata on it. However because of this, when the target server boots 
>> up, the md driver shoves it into md127. And because of this, the iSCSI 
>> target daemon (tgtd) wont export the device as its now part of a raid 
>> device.
>> The partition type is 0x83, not 0xfd.
>>
>> RHEL6 2.6.32-71
>>     
>
> The md driver isn't auto-creating this.  
> mdadm is being run and being asked to create this, possibly implicitly.
>
> Exactly how you stop this from happening depends on where it is an initrd
> script or a boot script that is doing it, and which version of mdadm you have.
>
> If you have 3.0 or later, then putting
>    AUTO -all
>
> in mdadm.conf might be enough.
> If you have a 2.x, you probably need to tell the init script not to run
> mdadm, maybe edit the script, maybe set some default variable.  I know little
> about RHEL and so cannot suggest specifics.
>
> 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
>   
Youre right. I removed every single md-related init script so I didnt 
think mdadm was doing it. But apparently I forgot about udev. I replaced 
mdadm with a script to dump out a bunch of info and found that udev is 
calling `mdadm -I /dev/sdb1`. Any idea where this might be configured 
at? I did a recursive grep for 'mdadm' in the entire /etc and found 
nothing but init scripts and a little selinux stuff  (nothing in /etc/udev).

-Patrick

Re: disable creation of md127

[Patrick H.]

Sent: Fri Dec 10 2010 15:36:01 GMT-0700 (Mountain Standard Time)
From: Patrick H. <linux-raid@feystorm.net>
To: linux-raid@vger.kernel.org
Subject: Re: disable creation of md127
> Sent: Fri Dec 10 2010 14:58:59 GMT-0700 (Mountain Standard Time)
> From: Neil Brown <neilb@suse.de>
> To: Patrick H. <linux-raid@feystorm.net> linux-raid@vger.kernel.org
> Subject: Re: disable creation of md127
>> On Fri, 10 Dec 2010 14:38:30 -0700 "Patrick H." 
>> <linux-raid@feystorm.net>
>> wrote:
>>
>>  
>>> How can I prevent the MD driver from auto-creating md127 on boot?
>>> I have a server which is exporting /dev/sdb1 via iSCSI. The remote 
>>> client for this device is using it in a raid device so it has raid 
>>> metadata on it. However because of this, when the target server 
>>> boots up, the md driver shoves it into md127. And because of this, 
>>> the iSCSI target daemon (tgtd) wont export the device as its now 
>>> part of a raid device.
>>> The partition type is 0x83, not 0xfd.
>>>
>>> RHEL6 2.6.32-71
>>>     
>>
>> The md driver isn't auto-creating this.  mdadm is being run and being 
>> asked to create this, possibly implicitly.
>>
>> Exactly how you stop this from happening depends on where it is an 
>> initrd
>> script or a boot script that is doing it, and which version of mdadm 
>> you have.
>>
>> If you have 3.0 or later, then putting
>>    AUTO -all
>>
>> in mdadm.conf might be enough.
>> If you have a 2.x, you probably need to tell the init script not to run
>> mdadm, maybe edit the script, maybe set some default variable.  I 
>> know little
>> about RHEL and so cannot suggest specifics.
>>
>> 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
>>   
> Youre right. I removed every single md-related init script so I didnt 
> think mdadm was doing it. But apparently I forgot about udev. I 
> replaced mdadm with a script to dump out a bunch of info and found 
> that udev is calling `mdadm -I /dev/sdb1`. Any idea where this might 
> be configured at? I did a recursive grep for 'mdadm' in the entire 
> /etc and found nothing but init scripts and a little selinux stuff  
> (nothing in /etc/udev).
>
> -Patrick
> -- 
> 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

Nevermind, found it. /lib/udev/rules.d/65-md-incremental.rules
Thanks for pointing me back at mdadm (had ruled it out after I removed 
the init scripts) :-)

Re: disable creation of md127

[Neil Brown]

On Fri, 10 Dec 2010 15:36:01 -0700 "Patrick H." <linux-raid@feystorm.net>
wrote:

> Sent: Fri Dec 10 2010 14:58:59 GMT-0700 (Mountain Standard Time)
> From: Neil Brown <neilb@suse.de>
> To: Patrick H. <linux-raid@feystorm.net> linux-raid@vger.kernel.org
> Subject: Re: disable creation of md127
> > On Fri, 10 Dec 2010 14:38:30 -0700 "Patrick H." <linux-raid@feystorm.net>
> > wrote:
> >
> >   
> >> How can I prevent the MD driver from auto-creating md127 on boot?
> >> I have a server which is exporting /dev/sdb1 via iSCSI. The remote 
> >> client for this device is using it in a raid device so it has raid 
> >> metadata on it. However because of this, when the target server boots 
> >> up, the md driver shoves it into md127. And because of this, the iSCSI 
> >> target daemon (tgtd) wont export the device as its now part of a raid 
> >> device.
> >> The partition type is 0x83, not 0xfd.
> >>
> >> RHEL6 2.6.32-71
> >>     
> >
> > The md driver isn't auto-creating this.  
> > mdadm is being run and being asked to create this, possibly implicitly.
> >
> > Exactly how you stop this from happening depends on where it is an initrd
> > script or a boot script that is doing it, and which version of mdadm you have.
> >
> > If you have 3.0 or later, then putting
> >    AUTO -all
> >
> > in mdadm.conf might be enough.
> > If you have a 2.x, you probably need to tell the init script not to run
> > mdadm, maybe edit the script, maybe set some default variable.  I know little
> > about RHEL and so cannot suggest specifics.
> >
> > 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
> >   
> Youre right. I removed every single md-related init script so I didnt 
> think mdadm was doing it. But apparently I forgot about udev. I replaced 
> mdadm with a script to dump out a bunch of info and found that udev is 
> calling `mdadm -I /dev/sdb1`. Any idea where this might be configured 
> at? I did a recursive grep for 'mdadm' in the entire /etc and found 
> nothing but init scripts and a little selinux stuff  (nothing in /etc/udev).

/lib/udev/rules.d/64-...something

You can disable this by creating an empty file with the same name
in /etc/udev/rules.d ... which might be kinder to the package management
system.

NeilBrown