What is hot spare HDD?

Hot spare disks are preparatory disk drives that are kept on active standby for use when a disk drive fails. The Global Hot Spare function enables hot spare disks to be used for any RAID group. When a disk drive in a RAID group fails, data on the disk drive is rebuilt automatically on the hot spare disk in background.

Should I use hot spare?

It’s true that a Hot-Spare helps to minimize the duration of a degraded array state but our goal of creating a Redundant Array of Inexpensive Disks is to continue operation and not to lose data in the event of a drive failure. Anything that increases the risk of data loss is a bad idea.

What is hot spare?

A hot spare, also called a hot standby, is a backup component that can be placed into service immediately when a primary component fails. The adjective “hot” means that the backup component (which can be hardware or software) can replace the primary component without shutting the system down.

What is the purpose of hot spares in a RAID implementation?

The hot spare disk reduces the mean time to recovery (MTTR) for the RAID redundancy group, thus reducing the probability of a second disk failure and the resultant data loss that would occur in any singly redundant RAID (e.g., RAID-1, RAID-5, RAID-10).

What if RAID controller fails?

If your RAID controller fails, your data may or may not be accessible, even if there is no damage to the hard drive’s magnetic platters – it all depends on the level of RAID. This means that one disk in the array can fail and the inherent ‘redundancy’ will automatically recover all the data within the controller.

How does a hot spare work?

A hot spare disk is a disk that is assigned to a storage system and is ready for use, but is not in use by a RAID group and does not hold any data. If a disk failure occurs within a RAID group, the hot spare disk is automatically assigned to the RAID group to replace the failed disks.

Does RAID 10 need a hot spare?

RAID 10 requires a minimum of four drives. Adding two additional drives to the array will add another RAID 1. The RAID 10 + hot spares must use at least five drives, one spare in addition to the RAID 10 drives. To add another RAID 1, you would need seven drives total because at least one hot spare drive is required.

What is better a RAID 5 with a hot spare or RAID 6?

RAID 5 should never exist with a hot spare (warm spare.) RAID 6 is always a better use of the same drive count. There is no space/capacity advantage or cost advantage to the RAID 5 solution (but some small performance advantage) but it does a ton for mitigating things like URE risk.

When one disk fails in a RAID 5 array without a hot spare?

When a single disk in a RAID 5 disk array fails, the disk array status changes to Degraded. The disk array remains functional because the data on the failed disk can be rebuilt using parity and data on the remaining disks. If a hot-spare disk is available, the controller can rebuild the data on the disk automatically.

What does a hot spare disk drive do?

Hot spares act as standby drives in RAID 1, RAID 5, or RAID 6 volume groups. They are fully functional drives that contain no data. If a drive fails in the volume group, the controller automatically reconstructs data from the failed drive to a hot spare.

Can a hot spare drive be used in a pool?

A hot spare drive is not dedicated to a specific volume group. Instead, you can use a hot spare drive for any failed drive in the storage array with the same capacity or smaller capacity. A hot spare drive must be of the same media type (HDD or SSD) as the drives that it is protecting. NOTE: Hot spare drives are not supported with pools.

Is there a hot spare drive in 3PAR?

One of the differences with 3PAR is that there isn’t a hot spare drive but there is hot spare capacity that is striped across the same type drives. So if you have a two tier 3PAR system – let’s say with SSD and nearline HDD, the spare capacity needed for a drive failure is striped across the SSD and nearline tier.

How to assign a hard drive to a global hot spare?

Using the PERC BIOS Controller 1 Perform the following steps to create global hot spares: 2 Press the down arrow key to highlight a physical disk to change to a global hot spare. 3 Press to display the menu of available actions. 4 Press the down arrow key to highlight Make Global HS and press . More