RAID 1 and how can you tell it's working

[Magueta]

Recently I recommended setting up RAID 1 for a client who has had poor luck with hard drives and data loss. The customer was interested but wanted to know how one could tell that the data was actually being mirrored on the other drive. Because we all know that backups should be tested this seemed like a good question to know the answer to.
So, how can you verify that there's data on the mirrored drive of a hardware RAID 1 setup?

Thanks

Joe

[bradfordgd]

I suppose it depends what you are using to do the mirroring. If you do software RAID that's mirroring one disk to another, you should be able to mount the second drive and compare it to the first using diff or something. They should be identical. Depending on the exact software you use, there could even be a software vendor tool to show you this. If you're using hardware RAID the hardware vendor usually supplies software that'll show you the state of the mirror.

[Magueta]

I understand that there are methods in place for knowing the state of the mirror and even the fitness of the individual drives but how can one check the integrity of the data on a hardware mirror? I've checked with the tech support for a 3ware card about this same question and they more or less said the same thing; that outside of removing a single drive it was not possible, however, they did say that in a mirror both drives are used as sources as well as destinations for data so I guess barring something visible to the controller or operating system itself the data would come back corrupt if it had poor integrity.
Thanks for the reply

Joe