Non-Destructive Linux MD RAID 10 Growth?

coliver

Not sure. I believe the man page says it can only grow RAID 0/1/5/6

scottalanmiller

From kernel.org: When new disks are added, existing raid partitions can be grown to use the new disks. After the new disk was partitioned, the RAID level 1/4/5/6 array can be grown for example using this command

scottalanmiller

@dafyre said:

Upgrade one drive to a larger drive, let the rebulid complete... and repeat?

In the end, it may require a reboot so that the raid controller will recognize the larger disks.

Cloud, can't switch drives.

scottalanmiller

@coliver said:

Not sure. I believe the man page says it can only grow RAID 0/1/5/6

That's always been my understanding. Hoping that there is a way to grow a RAID 0 stripe, but I am pretty sure that there is not.

scottalanmiller

In this particular use case, a span would be acceptable rather than a move to grow the RAID 0 stripe. But I don't know of that being an option either, sans LVM.

scottalanmiller

This link suggests that it can be done, but not in this scenario...

http://serverfault.com/questions/497661/mdadm-growing-a-raid0-array-weirdness

scottalanmiller

Newer man page for MDADM adds RAID 0...

Grow (or shrink) an array, or otherwise reshape it in some way. Currently supported growth options including changing the active size of component devices and changing the number of active devices in Linear and RAID levels 0/1/4/5/6, changing the RAID level between 0, 1, 5, and 6, and between 0 and 10, changing the chunk size and layout for RAID 0,4,5,6, as well as adding or removing a write-intent bitmap.

dafyre

If it's a cloud system why are you using RAID 10 with it?

coliver

From http://lwn.net/Articles/565591/

RAID10 arrays can be reshaped to change the number of devices,
change the chunk size, or change the layout between 'near'
and 'offset'.
This will always change data_offset, and will fail if there is no
room for data_offset to be moved.

Dashrender

@dafyre said:

If it's a cloud system why are you using RAID 10 with it?

I was wondering the same.

scottalanmiller

@dafyre said:

If it's a cloud system why are you using RAID 10 with it?

I didn't build it.

dafyre

@scottalanmiller said:

@dafyre said:

If it's a cloud system why are you using RAID 10 with it?

I didn't build it.

Sure... Sure... Blame it on the other guys... If you can't fix it the easy way, at least you have a chance to redo it right.