1. Dedicated Hot-Spare: A disk that stands ready to take the place of any disk that fails - any disk that is part of the array to which the hot-spare is assigned. If you have a 2x1TB RAID 1 and a 3x1TB RAID 5, you can assign the hot-spare to protect ONLY the RAID 5, so if a disk from the RAID 1 fails, it will not rebuild, but if a disk in the RAID 5 fails, it WILL rebuild in that failed disk's place. Global Hot-Spare: A disk that stands ready to take the place of any disk that fails - any disk that is part of any array. In the scenario above, you could assign the disk as a global hot-spare, so regardless of which array the failing disk belongs to, the hot-spare will rebuild in its place. A hot-spare must be at least as large as the drive it is to replace, and a hot-spare must be the same drive type (SAS/SATA) as the drive it is to replace.   This is not true. 2.  It depends on your configuration. Obviously you are not just running a single RAID 5, or with two disks in a READY state, your array/data would be gone. So, we need to know exactly the configuration you are running. 3.  Yes, you should start with the other two, with the array fully redundant and healthy before addressing the pred fail disk. You will need to FORCE it offline before replacing it ... WHEN you are ready to do so.
Hello,  I recently replaced a drive in a poweredge 2950 with a perc 5/i running RAID-5. There are 4 disks on connector 0 and 2 disks on connector 1. Drive replaced is 0:0:1 and is stuck in a Ready state.  I've attempted to add as a hot spare but cannot seem to get this drive to come online.  While checking this out, drive 1:0:5 is also stuck in a Ready state and not online.( i believe this was replaced in the past by a former employee)  1.  Can someone explain global hot spare vs. dedicated hot spare and if i would want a disk to be one.  I find this very confusing and dont understand the reading i keep finding.  I was even told that the hot spare would only pick up the slack for the connector it was attached to?  2.  How do i make disk 0:0:1 online and 1:0:5 online?  3. Disk 0:0:0 is also in a predicted failure state and i have a drive for that but i would like to start with these other two.  I understand it is unlikely to have two failed drives at the same time, however we are dealing with drives from 2006   Any help would be much appreciated.  I apologize in advance for any terminology i hacked up and also for my ignorance in this subject.  v/r Blair
replaced drive perc5i