# What happens to geli on a RAID-5 array when a disk fails?



## ericr (Jul 14, 2009)

I've checked the man pages and the Handbook, but can't find any info about the interaction of geli and RAID.

I've got a 3ware RAID controller with a 3 disk RAID-5 array and one hot spare disk, running 7.2-RELEASE.

So I want to encrypt one partition of the array, but I'm wondering what will happen when a disk fails and the controller swaps in the hot spare disk...

How will geli cope with that?

Will all the encrypted data be destroyed/corrupted?

Will everything just keep on working, and I can replace the dead disk and make it the new hot spare?

I could go fail a disk in the array and see what happens, but I'm kinda hoping to learn more before I try that.

Thanks!

- ericr


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## phoenix (Jul 14, 2009)

Nothing strange will happen.  The RAID controller will automatically "drop" the dead disk, "add" the hot-spare, and copy data to the "new" disk until the array is completely rebuilt.

As far as anything on top of that is concerned, nothing happens.  That's the whole point of RAID5 (or RAID6).

You just go on about your business.  Replace the dead drive, and make it the new hot-spare.

That's the beauty of hardware RAID ... it all happens below the level of the OS, so the OS never notices.


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