Storage Pool Expansion on EMC VNX/MCx arrays is a simple, straightforward task that can be done to increase capacity, performance or both.
It is an online operation (NDU) but I always try to initiate it when load on an array is non-peak. The process is just like a Fast VP data relocation.
Of course there’s more than one way to do this task, the GUI way and the fun way with CLI!
Method 1 . Naviseccli.
This utilizes the storagepool command with the –expand option.
In my case I will be expanding Storage Pool ID # 4 with 5 x disks in 2_1_10 :14 into an existing Performance tier. ( I can omit the –rtype option to choose a RAID type). If you want to skip the background verify task you can use the –initialverify no or use yes and limit the rate.
naviseccli –h array-spa storagepool –expand –id 4 –disks 2_1_10 2_1_11 2_1_12 2_1_13 2_1_14
And we’re off. Progress of the rebuild can be monitored with;
naviseccli -h array-spa storagepool -list -id 4 -all | select-string -pattern 'Rebalance Percent Complete'
To watch it progress in actual time, you can use the following Powershell script snippet to call and filter the naviseccli command;
start-sleep -s 3
$progress = (naviseccli -h array-spa storagepool -list -id 4 -all | select-string -pattern 'Rebalance Percent Complete')
write-host -nonewline "`r$progress"
While ($progress -notlike 'Rebalance Percent Complete: N/A')
…….and done. (that’s 100.00% ! )
Method 2. – Unisphere
Select your pool, click expand. Either accept the disks chosen for you or click on Manual and select them yourself
Leave the default options (unless you want to increase/decrease the background verify priority which scans the new disk looking for any latent soft media errors) and click ok.
Job done. This will trigger a “Rebalance” of the pool tier. Progress can be checked by going into the Pool properties, where the State will have changed from “Ready” to Rebalancing with a “% complete” counter as the operation progresses.
You can also get information from the Tiering Tab, where you can see the time remaining, data to be moved (intra-tier).