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DKNUCKLES
Asked: 2011-10-27 05:27:04 +0800 CST

Is it safe to transfer RAID 5 disks from one server to another?

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I have (what I assume) will be a relatively simple question.

I have an old file server that I've decommissioned and replaced. I would like to re-use the hardware from the old file server at our satellite office for offsite backup storage. Because I'm paranoid I would like to keep the data on these disks (despite the fact it's all been migrated and we have backups of the server). To that end, I would like to take the 3 hard drives out (server was running a RAID 5) and put 3 new ones in and install the OS and configure from scratch.

Assuming the hard drives are clearly labelled as drive 0, 1, 2, can they safely be transferred into another server with a different RAID card running RAID 5 (with the drives installed in the same order they were on the old server)? In short, is that data safe?

hard-drive raid5

3 Answers

  1. Best Answer

    In most cases the array metadata on the disks will work with a controller from the same family. For example, the Mylex DAC-FFX series of SAN controllers would take arrays formatted on an ExtremeRAID 3000 card (which was essentially the same controller on a PCI card). The same is true of HP (nee Compaq) Smartarray 64xx and (I believe) PXXX controllers and MSA1K/2K series SANs.

    If your RAID controller is from a different manufacturer/series then it will probably not work, however if it is within the same family from the same manufacturer, then it probably will. It is also quite likely to work on later models from the same manufacturer. Most Adaptec SCSI, SAS and SATA RAID controllers produced in about the past 10 years or so use essentially the same firmware. I guess that kit from LSI or 3Ware is similar in this respect, although I've never used them.

    Note that some vendors like IBM and Dell sell OEM versions of controllers from third parties, and the models may come from different manufacturers. You would need to do your homework in this case with (for example) a Dell PERC or an IBM ServerRAID.

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  2. Most likely you won't have to label the drives. I've never seen a RAID controller that stores metadata on the controller only. You should be able to just attach the drives in whatever order, and the RAID controller should be able to see the volumes (if it is compatible). I do this regularly with HP P410 controllers.

    If high performance isn't needed, you could also use software RAID. That's what I do with offsite remote backup machines. I don't have spare parts for those old servers, so I configured a Software RAID 5 on a Linux box.

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  3. I would say there are too many "shoulds", "maybes", "mights" and "depends" to answer in the positive to your question.

    I would say that you can't do it as you are changing hardware, if you're that paranoid after data backups and migration etc, then you shouldn't reuse that server.

    It is possible that you could transfer to another of the same RAID controller, but I don't think I would ever bet on it working all of the time.

    And of course, the chance of something going wrong will be proportional to how badly you needed the data there and then ...

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