I remember seeing one with an example migrating from an old fashioned filesystem on a partition to a new filesystem on a mirrored lvm logical volume but one only one side of the mirror is set up at this time.
First I need to copy stuff from what will become the second side of the mirror to filesystem on the first side or the mirror
Then I will be ready to follow the rest of the tutorial and build and attach the second side of the mirror.
Wish I could remember where I saw that tutorial.
Want to embellish the example and stripe each side of the mirror.
Understanding a mirrored pair of stripes, seems easier than understanding a striped pair of mirrors.
But this seems like a place where counterintuitive results are not a big surprise.
I can do mirroring and striping in lvm, mdadm, or a hardware raid controller. There are lots of configurations to ponder.
What about recovery after a hardware raid controller?
What are the chances of being able to replace the controller and start up successfully from drives? I know that assuming the failed controller did write bad stuff to the drives while it was crashing and burning.
I would not be surprised if the controller firmware revisions had to match. I would be surprised but not astonished if the board hardware revision level had to match, too. I hope we are past those days.
Anybody know about the LSI Logic MegaRAID 8480 Storage controller in particular.
on 6-7-2008 9:35 AM drew einhorn spake the following:
I remember seeing one with an example migrating from an old fashioned filesystem on a partition to a new filesystem on a mirrored lvm logical volume but one only one side of the mirror is set up at this time.
First I need to copy stuff from what will become the second side of the mirror to filesystem on the first side or the mirror
Then I will be ready to follow the rest of the tutorial and build and attach the second side of the mirror.
Wish I could remember where I saw that tutorial.
Want to embellish the example and stripe each side of the mirror.
Understanding a mirrored pair of stripes, seems easier than understanding a striped pair of mirrors.
But this seems like a place where counterintuitive results are not a big surprise.
I can do mirroring and striping in lvm, mdadm, or a hardware raid controller. There are lots of configurations to ponder.
What about recovery after a hardware raid controller?
What are the chances of being able to replace the controller and start up successfully from drives? I know that assuming the failed controller did write bad stuff to the drives while it was crashing and burning.
I would not be surprised if the controller firmware revisions had to match. I would be surprised but not astonished if the board hardware revision level had to match, too. I hope we are past those days.
Anybody know about the LSI Logic MegaRAID 8480 Storage controller in particular.
I know that with 3ware controllers, they are always backward compatible, and will sell you a controller that will work. As to the "bad" activity, nothing will mitigate backups.
On Mon, Jun 9, 2008 at 10:48 AM, Scott Silva ssilva@sgvwater.com wrote:
on 6-7-2008 9:35 AM drew einhorn spake the following:
Anybody know about the
LSI Logic MegaRAID 8480 Storage controller in particular.
I know that with 3ware controllers, they are always backward compatible,
and will sell you a controller that will work. As to the "bad" activity, nothing will mitigate backups.
Yes, backups are absolutely neccessary, but one hopes that in many cases a quicker, easier, recovery is possible. It is desirable that the filesystems will come up with old drives and a new controller. But sometimes that is just not possible if a failing controller wrote bad stuff on the drives.
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drew einhorn -
Scott Silva