sorry that i must missed u reply.

is there any technical issue that lead not to be implemented?

is there any place to find previous discussion on this? i try the google
but fail. i do no know which key word can find that. thx.

ming

On Thursday November 4, mingz [at] ele.uri.edu wrote:
> Hi, folks?
>
> I would like to know if current RAID1 support or willing to support a
> RAID1 with a write only device? For example, u can setup 2 disks to
form
> a raid1, you fork 2 writes to both disks while you only read from one.
> this will be very useful for logging purpose or replication.

This functionality has been discussed, but have not been implemented
in a released kernel yet.

NeilBrown


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Ming Zhang wrote:

> is there any technical issue that lead not to be implemented?

No. In fact, it has been implemented. Both Peter T. Breuer and I have
come up with slightly different patches to implement the write only
functionality.

> is there any place to find previous discussion on this? i try the google
> but fail. i do no know which key word can find that. thx.

Try the archives of this mailing list:

http://marc.theaimsgroup.com/?l=linux-raid&r=1&w=2

This has been discussed a couple of times and patches have been posted
to the list in the past.

--
Paul



> On Thursday November 4, mingz [at] ele.uri.edu wrote:
>
>>Hi, folks?
>>
>>I would like to know if current RAID1 support or willing to support a
>>RAID1 with a write only device? For example, u can setup 2 disks to
>
> form
>
>>a raid1, you fork 2 writes to both disks while you only read from one.
>>this will be very useful for logging purpose or replication.
>
>
> This functionality has been discussed, but have not been implemented
> in a released kernel yet.
>
> NeilBrown
>
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo [at] vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>

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On Wed, 2004-11-10 at 10:05, Paul Clements wrote:
> Ming Zhang wrote:
>
> > is there any technical issue that lead not to be implemented?
>
> No. In fact, it has been implemented. Both Peter T. Breuer and I have
> come up with slightly different patches to implement the write only
> functionality.
>
can u send me the patch then i can have a look?

> > is there any place to find previous discussion on this? i try the google
> > but fail. i do no know which key word can find that. thx.
>
> Try the archives of this mailing list:
>
> http://marc.theaimsgroup.com/?l=linux-raid&r=1&w=2
>
> This has been discussed a couple of times and patches have been posted
> to the list in the past.
>
i must be an idiot. i search again and can not find. even with either of
your two guys' name. :P i have to change my eyeglass again. sigh.

> --
> Paul
>
>
>
> > On Thursday November 4, mingz [at] ele.uri.edu wrote:
> >
> >>Hi, folks?
> >>
> >>I would like to know if current RAID1 support or willing to support a
> >>RAID1 with a write only device? For example, u can setup 2 disks to
> >
> > form
> >
> >>a raid1, you fork 2 writes to both disks while you only read from one.
> >>this will be very useful for logging purpose or replication.
> >
> >
> > This functionality has been discussed, but have not been implemented
> > in a released kernel yet.
> >
> > NeilBrown
> >
> >
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> > the body of a message to majordomo [at] vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
--
--------------------------------------------------
| Ming Zhang, PhD. Student
| Dept. of Electrical & Computer Engineering
| College of Engineering
| University of Rhode Island
| Kingston RI. 02881
| e-mail: mingz at ele.uri.edu
| Tel. (401) 874-2293
| Fax. (401) 782-6422
| http://www.ele.uri.edu/~mingz/
| http://crab.ele.uri.edu/gallery/albums.php
--------------------------------------------------


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Ming Zhang wrote:
> On Wed, 2004-11-10 at 10:05, Paul Clements wrote:
>
>>Ming Zhang wrote:
>>
>>
>>>is there any technical issue that lead not to be implemented?
>>
>>No. In fact, it has been implemented. Both Peter T. Breuer and I have
>>come up with slightly different patches to implement the write only
>>functionality.
>>
>
> can u send me the patch then i can have a look?

my patches are here:

http://parisc-linux.org/~jejb/md_bitmap/

you're looking for the async write portion of the code, which has the
write-only functionality in it (later patches do not contain that code,
so look at the older ones)

check the mailing list archives for discussion

Peter's patch is here:

http://marc.theaimsgroup.com/?l=linux-raid&m=109238533827986 &w=2


--
Paul
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