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@ele.uri.edu wrote:

quoted

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

quoted

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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