* auto assemble in read-only mode?
@ 2014-10-06 13:06 Errol Neal
2014-10-07 6:56 ` Errol Neal
0 siblings, 1 reply; 5+ messages in thread
From: Errol Neal @ 2014-10-06 13:06 UTC (permalink / raw)
To: Linux-RAID
hi folks. is it possible to assemble an md device in read-only mode?
after an array has been assembled, I know I can mark it as readonly with --misc -o /dev/md0 for example, but only after its been assembled it seems..
tia,
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: auto assemble in read-only mode?
2014-10-06 13:06 auto assemble in read-only mode? Errol Neal
@ 2014-10-07 6:56 ` Errol Neal
2014-10-07 7:15 ` NeilBrown
0 siblings, 1 reply; 5+ messages in thread
From: Errol Neal @ 2014-10-07 6:56 UTC (permalink / raw)
To: eneal; +Cc: Linux-RAID
On Mon, 10/06/2014 09:06 AM, Errol Neal <eneal@businessgrade.com> wrote:
> hi folks. is it possible to assemble an md device in read-only mode?
> after an array has been assembled, I know I can mark it as readonly with --misc -o /dev/md0 for example, but only after its been assembled it seems..
>
Hi again. No thoughts here?
I'm need to run a RAID1 device on two independent nodes (shared storage) and I'd like to assemble the device on the "slave" node in read-only mode to prevent any sync actions and etc.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: auto assemble in read-only mode?
2014-10-07 6:56 ` Errol Neal
@ 2014-10-07 7:15 ` NeilBrown
2014-10-07 12:31 ` Errol Neal
0 siblings, 1 reply; 5+ messages in thread
From: NeilBrown @ 2014-10-07 7:15 UTC (permalink / raw)
To: Errol Neal; +Cc: Linux-RAID
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On Tue, 7 Oct 2014 02:56:31 -0400 Errol Neal <eneal@businessgrade.com> wrote:
> On Mon, 10/06/2014 09:06 AM, Errol Neal <eneal@businessgrade.com> wrote:
> > hi folks. is it possible to assemble an md device in read-only mode?
> > after an array has been assembled, I know I can mark it as readonly with --misc -o /dev/md0 for example, but only after its been assembled it seems..
> >
>
> Hi again. No thoughts here?
Not even 18 hours since you last asked - what do you thing this is? The
Internet :-)
> I'm need to run a RAID1 device on two independent nodes (shared storage) and I'd like to assemble the device on the "slave" node in read-only mode to prevent any sync actions and etc.
Did you try adding the "--readonly" option to your --assemble command?
(Always best to report everything you tried and how it failed - requires less
guess work).
I hope you don't expect too much of a filesystem mounted from such an array
while the other node is writing to the array...
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
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: auto assemble in read-only mode?
2014-10-07 7:15 ` NeilBrown
@ 2014-10-07 12:31 ` Errol Neal
2014-10-07 23:33 ` NeilBrown
0 siblings, 1 reply; 5+ messages in thread
From: Errol Neal @ 2014-10-07 12:31 UTC (permalink / raw)
To: NeilBrown; +Cc: Linux-RAID
On Tue, 10/07/2014 03:15 AM, NeilBrown <neilb@suse.de> wrote:
> On Tue, 7 Oct 2014 02:56:31 -0400 Errol Neal <eneal@businessgrade.com> wrote:
>
> > On Mon, 10/06/2014 09:06 AM, Errol Neal <eneal@businessgrade.com> wrote:
> > > hi folks. is it possible to assemble an md device in read-only mode?
> > > after an array has been assembled, I know I can mark it as readonly with --misc -o /dev/md0 for example, but only after its been assembled it seems..
> > >
> >
> > Hi again. No thoughts here?
>
> Not even 18 hours since you last asked - what do you thing this is? The
> Internet :-)
HAHA. I tend to feel ignored on large mailing lists lol. Need to see my therapist again ;)
>
> > I'm need to run a RAID1 device on two independent nodes (shared storage) and I'd like to assemble the device on the "slave" node in read-only mode to prevent any sync actions and etc.
>
> Did you try adding the "--readonly" option to your --assemble command?
> (Always best to report everything you tried and how it failed - requires less
> guess work).
I did that previously and mdadm told me that "option --readonly not valid in assemble mode". E.g. "mdadm --assemble --scan --readonly".
The readonly flag seems like it can only be used after a device has been assembled. So for example, after the device has been assembled, I can
run mdadm --misc -o /dev/md0 but that is not always safe for my use case.
> I hope you don't expect too much of a filesystem mounted from such an array
> while the other node is writing to the array...
>
I don't. It will be read-only until the pacemaker RA promotes the slave.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: auto assemble in read-only mode?
2014-10-07 12:31 ` Errol Neal
@ 2014-10-07 23:33 ` NeilBrown
0 siblings, 0 replies; 5+ messages in thread
From: NeilBrown @ 2014-10-07 23:33 UTC (permalink / raw)
To: Errol Neal; +Cc: Linux-RAID
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On Tue, 7 Oct 2014 08:31:34 -0400 Errol Neal <eneal@businessgrade.com> wrote:
> On Tue, 10/07/2014 03:15 AM, NeilBrown <neilb@suse.de> wrote:
> > On Tue, 7 Oct 2014 02:56:31 -0400 Errol Neal <eneal@businessgrade.com> wrote:
> >
> > > On Mon, 10/06/2014 09:06 AM, Errol Neal <eneal@businessgrade.com> wrote:
> > > > hi folks. is it possible to assemble an md device in read-only mode?
> > > > after an array has been assembled, I know I can mark it as readonly with --misc -o /dev/md0 for example, but only after its been assembled it seems..
> > > >
> > >
> > > Hi again. No thoughts here?
> >
> > Not even 18 hours since you last asked - what do you thing this is? The
> > Internet :-)
>
> HAHA. I tend to feel ignored on large mailing lists lol. Need to see my therapist again ;)
>
> >
> > > I'm need to run a RAID1 device on two independent nodes (shared storage) and I'd like to assemble the device on the "slave" node in read-only mode to prevent any sync actions and etc.
> >
> > Did you try adding the "--readonly" option to your --assemble command?
> > (Always best to report everything you tried and how it failed - requires less
> > guess work).
>
> I did that previously and mdadm told me that "option --readonly not valid in assemble mode". E.g. "mdadm --assemble --scan --readonly".
That tells me use are using a version of mdadm earlier than 3.3.
"--assemble --readonly" support was added for 3.3.
NeilBrown
> The readonly flag seems like it can only be used after a device has been assembled. So for example, after the device has been assembled, I can
> run mdadm --misc -o /dev/md0 but that is not always safe for my use case.
>
>
>
> > I hope you don't expect too much of a filesystem mounted from such an array
> > while the other node is writing to the array...
> >
>
> I don't. It will be read-only until the pacemaker RA promotes the slave.
> --
> 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
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^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-10-07 23:33 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2014-10-06 13:06 auto assemble in read-only mode? Errol Neal
2014-10-07 6:56 ` Errol Neal
2014-10-07 7:15 ` NeilBrown
2014-10-07 12:31 ` Errol Neal
2014-10-07 23:33 ` NeilBrown
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