System Settings : Dashboard : RAID Monitor widget : Hot-swapping hard disks
 
Hot-swapping hard disks
If a hard disk on a FortiManager unit fails, it must be replaced. The hard disk can be replaced while the FortiManager unit is running, also known as hot swapping.
The Disk Monitor widget indicates a failed disk, including its RAID level, but does not give specific information about when the disk failed. To identify which hard disk failed, read the relevant log message in the Alert Message Console widget (see “Alert Message Console widget”).
To hot-swap a hard disk:
 
Electrostatic discharge (ESD) can damage FortiManager equipment. Only perform the procedures described in this document from an ESD workstation. If no such station is available, you can provide some ESD protection by wearing an anti-static wrist or ankle strap and attaching it to an ESD connector or to a metal part of a FortiManager chassis.
When replacing a hard disk, you need to first verify that the new disk has the same size as those supplied by Fortinet and has at least the same capacity as the old one in the FortiManager unit. Installing a smaller hard disk will affect the RAID setup and may cause data loss. Due to possible differences in sector layout between disks, the only way to guarantee that two disks have the same size is to use the same brand and model.
The size provided by the hard drive manufacturer for a given disk model is only an approximation. The exact size is determined by the number of sectors present on the disk.
1. Go to System Settings > General > Dashboard.
2. In the Unit Operation widget, click Shutdown.
3. Click OK.
4. Remove the faulty hard disk and replace it with a new one.
5. Restart the FortiManager unit.
The FortiManager unit will automatically add the new disk to the current RAID array. The status appears on the console. After the FortiManager unit boots, the widget will display a green check mark icon for all disks and the RAID Status area will display the progress of the RAID re-synchronization/rebuild.
 
Once a RAID array is built, adding another disk with the same capacity will not affect the array size until you rebuild the array by restarting the FortiManager unit.