force spare to sync

force spare to sync

[Michael]

I've been messing with a new raid 1 system with hot swap bays and it 
occurred to me that in a raid/boot situation, the spare drive is not 
sync'd and has no boot track. Is there a way to force the spare drive 
to sync to the "master" set so that lilo can be run on that drive to 
place a boot track with the appropriate information... or is there a 
way to hold the spare in sync. This need not be done for the entire 
disk, only the raid 1 boot partition. I can't see an easy way to do 
this with the current tools, it might be a nice option to add to 
future I'mplimentations.

Michael
Michael@Insulin-Pumpers.org

Re: force spare to sync

[Neil Brown]

On Thursday November 13, michael@insulin-pumpers.org wrote:
> I've been messing with a new raid 1 system with hot swap bays and it 
> occurred to me that in a raid/boot situation, the spare drive is not 
> sync'd and has no boot track. Is there a way to force the spare drive 
> to sync to the "master" set so that lilo can be run on that drive to 
> place a boot track with the appropriate information... or is there a 
> way to hold the spare in sync. This need not be done for the entire 
> disk, only the raid 1 boot partition. I can't see an easy way to do 
> this with the current tools, it might be a nice option to add to 
> future I'mplimentations.

If you want the spare to be in-sync with the rest of the array, then
it is not a spare, it is full member.

i.e. instead of making a RAID1 array with 2 drives and one space, make
it with three drives and no spare.

NeilBrown

Re: force spare to sync

[Michael]

> On Thursday November 13, michael@insulin-pumpers.org wrote:
> > I've been messing with a new raid 1 system with hot swap bays and it 
> > occurred to me that in a raid/boot situation, the spare drive is not 
> > sync'd and has no boot track. Is there a way to force the spare drive 
> > to sync to the "master" set so that lilo can be run on that drive to 
> > place a boot track with the appropriate information... or is there a 
> > way to hold the spare in sync. This need not be done for the entire 
> > disk, only the raid 1 boot partition. I can't see an easy way to do 
> > this with the current tools, it might be a nice option to add to 
> > future I'mplimentations.
> 
> If you want the spare to be in-sync with the rest of the array, then
> it is not a spare, it is full member.
> 
> i.e. instead of making a RAID1 array with 2 drives and one space,
> make it with three drives and no spare.
> 
> NeilBrown
> 
Can you really make a 3 partition raid 1 with no spare???? And all 3 
partitions will remain in sync???  I haven't dug into the kernel 
code, but somehow that doesn't seem logical..... but wadda I know???

Michael
Michael@Insulin-Pumpers.org

Re: force spare to sync

[Neil Brown]

On Thursday November 13, michael@insulin-pumpers.org wrote:
> > 
> > If you want the spare to be in-sync with the rest of the array, then
> > it is not a spare, it is full member.
> > 
> > i.e. instead of making a RAID1 array with 2 drives and one space,
> > make it with three drives and no spare.
> > 
> > NeilBrown
> > 
> Can you really make a 3 partition raid 1 with no spare???? And all 3 
> partitions will remain in sync???  I haven't dug into the kernel 

Certainly you can.  There is nothing magic a "2" in raid1.  You can
have a RAID1 array of 27 drives if you like and they will always be
kept in sync.

> ..... but wadda I know???

enough to ask questions, which is a good start.

NeilBrown