TechMike’s RAID Case Files: If Your System Board Crashes, Can You Physically Move the RAID Array to a New System?
You have a massive RAID array with several drives in a server. Disaster strikes, and the system board crashes. Recreating the RAID arrays from a backup could take a very long time, to say nothing of the reading/writing wear & tear on your drives. Wouldn’t it be great if you can just take all those functioning drives that house your RAID virtual disk(s) and install them in a new server and be up and running?
In this post, we’ll cover the basics so you can have a high-level understanding of the considerations in moving the physical resources of a RAID array to a new device.
Can it be done? If so, what are the considerations?
Enterprise servers are designed for flexibility. You can physically transfer the RAID array hardware from one server to another with no impact on data in most situations.
Here are some different scenarios during migrations from a RAID array physical hardware to a new server.
Transferring hard drives and a RAID controller between the same model server is ideal. For example, from a Dell R730 to another R730 should pose no issues – assuming, of course, that the drive bays are the same form factor, e.g., 3.5” hard drives could not go into a 2.5” form factor R730.
“Does it matter if the new server has different specs, such as different processors or RAM?”
It makes no difference other than whatever decreases (or increases) in the system specs will affect performance. A key is to ensure that you install the drives in the same order as they were in the previous server.
“What if the RAID card malfunctions? Can I just install a new RAID card in the same server?”
Yes. The RAID configuration is stored on both the controller and the drives. You would be prompted in System Set-Up that a foreign RAID configuration was found, and you would import the foreign configuration.
“What if I only transfer the drives and not the existing controller?”
Remember, the RAID configuration is stored on both the controller and the drives, so you can even physically transfer the RAID drives to a new server with a different RAID controller. Just be sure that the new RAID controller can manage the same RAID configuration (e.g., RAID 5, 10, etc.) as the previous controller, and if you have large drives (2 TB and above) that there is not a decrease in the new controller’s cache.
You would then import the foreign configuration.
“What if I have several RAID virtual disks in the same server? Would that pose any challenges?”
No. You would just need to import the foreign configuration for each RAID virtual disk.
You can even physically transfer RAID arrays between servers of the same brand but different models. For example, assuming the number of drives didn’t exceed the number of bays in the new server, you could move a RAID virtual disk(s) from a Dell R730 to a Dell R630. The same rules would apply as described above with importing a foreign configuration via System Set-Up. In some cases, you may do this not because of an issue in the current server, but the new server offers better specs – you could seamlessly move the RAID configuration to the new server to take advantage of the improved system.
“What about physically moving a RAID array between two servers that are different brands, such as from a Dell to an H.P. server?”
Now things get a bit more complicated. Since controllers of different brands will not have the same Input/Output, you should NOT attempt to boot from the RAID disk or Initiate Configuration in the System Set-Up (as this would erase the disks). So while you CANNOT migrate the RAID configuration on the drives – you can access the data on the drives. You’ll want to boot to an O.S., and from there, you can access the data on the RAID drives, as you could any other accessible drive. Note that this option should strictly be a last resort for data retrieval since you cannot import the RAID configuration -- and consequently, its backups and redundancy.
Enterprise servers – especially servers of the same manufacturer – have been designed to swap virtual disks between devices. The critical factors to keep in mind when physically migrating a RAID virtual disk to a different server are:
- Make sure you keep the drives in the same order that they were in from the previous server.
- RAID controllers of the same manufacturer will have the same I/O, which minimizes the variables involved.
- It is possible to migrate the data of a RAID array to a different brand server via physically moving the drives – however, proceed with caution as initiating a new configuration will erase the disks!
Are you in the market for upgrading an existing server with a RAID array you want to move to a new server? Drop us a line! We quote a build and walk you through the set-up – that’s what we do!