I have an HP Smart Array P400 RAID controller with six physical disks configured in RAID 5. Four of the physical disks are in "OK" state, one is in "Predictive Failure" state, and one is in "spare" state:
logicaldrive 1 (3.6 TB, RAID 5, OK)
physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SATA, 1 TB, Predictive Failure)
physicaldrive 1I:1:2 (port 1I:box 1:bay 2, SATA, 1 TB, OK)
physicaldrive 1I:1:3 (port 1I:box 1:bay 3, SATA, 1 TB, OK)
physicaldrive 1I:1:4 (port 1I:box 1:bay 4, SATA, 1 TB, OK)
physicaldrive 1I:1:5 (port 1I:box 1:bay 5, SATA, 1 TB, OK)
physicaldrive 1I:1:6 (port 1I:box 1:bay 6, SATA, 1 TB, OK, spare)
Is it safe to add (hpacucli controller slot=6 array A add drives=1:6) a "spare" drive to RAID 5 and once its drive type changes from "Spare Drive" to "Data Drive", then remove (either physically or maybe with hpacucli controller slot=6 array A remove drives=1:1) the HDD with the "Predictive Failure" state?
Wait until the drive fails or physically remove or replace it.
Seeing "Predictive Failure" in an indication to order a new drive.
The best course of action if to get a new drive and replace the failing drive with it (and not to rely on the spare rebuild).
You may disable this predictive failure drive and this will initiate rebuilding with spare drive if you have it in configuration(you have):
The second variant is to change drive spare activation mode:
But it is not supported for all controllers. The set-back command is
Note, that you may need to use hpacucli or hpssacli or ssacli commands depending on the controller and operating system.