Not like traditional storage, DDN SFA is In-Storage Processing with embedded file systems. It offers two types of file storage, GRIDScaler and EXAScaler technologies, which both have VMs on the controllers.

This makes a big different when you change the controller for it. You can't just pull one out then put a new one in.

Here is a short procedure just for your reference (remmeber to call your vendor support if you have).

1. Collect system information

On both controllers, run

show sub summary all

Doube check if there is subsystem fault

show subsystem fault

2. Stop VMs

Repeat the following command for all VMs on the problematic controller

app shutdown stack <stack No.>

3. Set VMs not to start on boot

Repeat the following command for all VMs on the problematic controller

app set stack <stack No.> AUTO_START FALSE

4. Replace controller

Makre sure all cables are connected correctly and firmly.

5. Swap old system disks back to new controller

There are three internal disks in each controller, put them to new controller in the same order.

6. Start new controller

7. Check if there is fault/error

SFA12K RAID[0]$ show subsystem fault
No SUBSYSTEM faults exist
Thu Jun 25 00:00:48 2015
SFA12K RAID[0]$ show controller fault
No CONTROLLER faults exist
Thu Jun 25 00:00:51 2015
SFA12K RAID[0]$ show channel fault
No CHANNEL faults exist
Thu Jun 25 00:00:57 2015
SFA12K RAID[0]$ show processor fault
No PROCESSOR faults exist
Thu Jun 25 00:01:02 2015

8. Bring VMs up

Repeat the following command for all VMs on the new  controller

app start stack <stack No.>

9. Set VMs start on boot

Repeat the following command for all VMs on the new  controller

app set stack <stack No.> AUTO_START FALSE

10. Check file system level if everything is good