software raid

[Bry Melvin]

Carl Karsten wrote:

> I have been messing around with software raid1 - mirroring 2 drives - 
> including the boot sectors. The goal is to be able to remove either 
> drive and still have a functioning system.
> 
> I realize that this is "not supported" given that "Add support for 
> software RAID." is on the http://grub.enbug.org/TodoList but I have 
> heard it can be done with some trickery: install grub on both drives 
and 
> rely on the fact that /dev/hda1 and /dev/hda2 and /dev/md0 are all 
"the 
> same thing" as long as md0 is the only one that gets written to.
> 
> But I did run into one problem:  if you have ide master and slave, 
and 
> you pull the master, the slave dissapears and the box/bios won't see 
it 
> so it won't boot from it.  so I am guessing I have to make each drive 
> the master on a seperate ide bus so that pulling one won't take out 
the 
> other.
> 
> Before I spend too much time trying to make this work, anyone know of 
a 
> HowTo that outlines this?
> 
> CarlFK
To: ubuntu-users at lists.ubuntu.com
In-Reply-To: <E1FM7lK-0000wT-Nf at esperanza.ubuntu.com>
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 rely on the fact that /dev/hda1 and /dev/hda2 and /dev/md0 are all 
"the 
> same thing" as long as md0 is the only one that gets written to.
> 
> But I did run into one problem:  if you have ide master and slave, 
and 
> you pull the master, the slave dissapears and the box/bios won't see 
it 
> so it won't boot from it.  so I am guessing I have to make each drive 
> the master on a seperate ide bus so that pulling one won't take out 
the 
 I haven't used software raid in some time, but wouldn't it be simpler to use CSEL instead of Master and Slave in this situation, then the controller wouldn't get confused with wrong jumper settings. IIRC ata 100/133/66 standard 80 wire ide cables (at least oem,,,) are usually intended for CSEL.
 
 Bryann

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<br><br><br> <br> <br> <pre><tt> rely on the fact that /dev/hda1 and /dev/hda2 and /dev/md0 are all <br>"the <br>> same thing" as long as md0 is the only one that gets written to.<br>> <br>> But I did run into one problem:  if you have ide master and slave, <br>and <br>> you pull the master, the slave dissapears and the box/bios won't see <br>it <br>> so it won't boot from it.  so I am guessing I have to make each drive <br>> the master on a seperate ide bus so that pulling one won't take out <br>the </tt></pre> I haven't used software raid in some time, but wouldn't it be simpler to use CSEL instead of Master and Slave in this situation, then the controller wouldn't get confused with wrong jumper settings. IIRC ata 100/133/66 standard 80 wire ide cables (at least oem,,,) are usually intended for CSEL.<br> <br> Bryann<br>
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