From: Michael Ralston <ralston@st...> - 2004-09-10 03:55:06
I've had an idea rolling over in my mind for a while and I was wondering if
anyone else had any feedback on it...
Here is the scenario..
Start up a User-Mode-Linux instance, with two udb devices backed by COW
Inside the UML, use linux software raid to mirror these two COWs
Then could you use mconsole to disable one of the udb devices, the uml
instance keeps running on the second udb.
While you have the udb disabled, merge the cow file and back it up.
Then renable the udb and linux software raid would mirror any changes that
happened on the other udb while it was disabled.
Would this work as described? If it did I figure you could set a cron job to
run on alternate days and merge udb0 on one day and ubd1 on the next day.
Sorry if I've used the wrong terms for cow files etc, I haven't used them
much, just had this little idea... Wondered if it would work.
From: Dick Middleton <dick@li...> - 2004-09-11 02:40:07
Michael Ralston wrote:
> I've had an idea rolling over in my mind for a while and I was wondering if
> anyone else had any feedback on it...
> Here is the scenario..
> Start up a User-Mode-Linux instance, with two udb devices backed by COW
> Inside the UML, use linux software raid to mirror these two COWs
You'd need a separate physical partition for each filesystem. You might
find it easier to use LVM. You create logical (rather than physical)
partitions (aka logical volumes). LVM has the capability to provide
snapshots of the lv specifically for the purpose of taking backups.