Extend Existing Array with Smart 221 Controller

[Iain Baikie]

I want to extend my existing array of 3 x 9.1Gb Ultra2 drives with an extra 18.2Gb Ultra 320 Drive. (i realise that i can only get 9.1Gb from the 18.2Gb drive). The Array Configuration utility recognises the unassigned drive but i cannot extend the existing array. I presume this is down to the controller. Is their a way that i can change the controller or update it?

[Janine Bertolo · Accepted solution]

Hi Iaian;

You're right - the controller is the problem.

The Smart221 does not allow array expansion.

You can replace each of the 3 9.1 GB drives with and 18 in sequence and let the array rebuild each time. When all three are replaced you can reclaim the additional space by adding a second logical drive using the ACU.

Otherwise, you can swith to a controller that supports the expansion (basically any of the Smart2 family besides the 2SL and 221, and any newer controller that has write-cache on it with the caution that an upgrade controller may require a different driver).

You can even put the 221 back into place after the expansion is done if you have a controller you can borrow temporarily from another machine.

Cheers,

Janine

[Iain Baikie]

Thanks v.much for the reply Janine. I was wondering if you could point me in the right direction of how to re-build each drive individually and how long each re-build would take.

[Janine Bertolo]

The procedure basically involves pulling out one hard drive at at time from the array and replacing it with a larger drive.

I would not recommend pulling an existing drive live because it hasn't been failed by the controller.

Down the server, remove a 9.1GB drive and replace it with an 18. Bring the server back up again - it will post with a message that drive array recovery is needed. Say yest to that option and bring up the OS.

Repeat this procedure until all the drives in the array have been replaced and rebuilt.

The duration of the rebuild is determined by the amount of existing data on the drive set. Presuming you are close to full and that's why you want to expand, you should have about 18GB of data to restripe.

It takes a minimum of 20 min/GB of data to rebuild - so each drive replacement will take you at least 6 hours.

Once all the drives are replaced you can run the Array Configuration Utility either online or from SmartStart and claim the additional space as a second logical drive on the array. Then use your OS to partition the drive.

The caution in this procedure is that you are *tricking* the controller into thinking a drive has failed. Should one of your existing drives fail at the same time as you are rebuilding onto a bigger one, you will lose your whole set.

So, as always, it is adviseable to take a current backup before beginning.

Hope that helps!

Janine

[Iain Baikie]

Ok, last one (promise!). Have decided to buy another two 18.2Gb Drives then add a second array to the existing set-up i.e. Array1 (3 x 9.1Gb Raid5) + Array2 (3 x 18.2Gb Raid5). What i was wondering was would my existing controller (Smart 221) be up for the task or not, or how much of degrade of performance would their be by having two seperate arrays, if any?

[Janine Bertolo]

Adding three 18.2GB drives as an Array B on your 221 controller is fully supported. You should not experience any degrade of performance at all.

You can use the ACU online to configure the new array without any interruption to a production environment.

Cheers!

Janine

[Iain Baikie]

CHEERS!! :-)