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(3-4) Hot Spare Disk
- Hot spare disk is recommended to enhance the availability of a unit.
- There is no upper limit for the number of hot spare disks.
- Hot spare disk
operates only in the same Disk Director (basic Disk Director: 16DE,192HDD,
Expansion Disk Director: 16DE, 192HDD) in a node.
- The default setting of hot spare operation does not allow the data to be written back. When the hot
spare disk is used and the failed disk is replaced, the replacement disk is defined as a new hot
spare disk.
In case you set the hot spare operation so that the data is to be written back, the data in the hot
spare disk will be transferred to the replacement disk, and after the completion of the "write
back", the hot spare disk will be used for the backup again. The operation of hot spare disk can be
set from the NEC Storage Manager.
- Hot spare disk can be used for the disk drives with the same interface.
- Hot spare disk is recommended to be the same capacity and the same rotation speed as the disks
in the pools. If different types of disks are used in different pools, there should also be different
types of hot spare disks accordingly.
- If there are multiple types of hot spare disks, the same type of disk as the disk in the defected
pool*1 is selectively used for backup.
- When the type of disk that used in the defected pool is not left as a hot spare disk, the hot spare
disks are used in the following order of priority.
1. The hot spare disk with the same type of interface, same capacity, same or more
rotation speed as the disk in the defected pool.
2. The hot spare disk with the same type of interface, same or more capacity as the disk in
the defected pool.
- As the recommended number of the hot spare disk is different between SAS and SATA Disk
Drives, refer to the tables in a) and b) below:
a) SAS Disk Drive
<Recommended number of Hot Spare Disk for SAS Disk Drive>
Conditions
In case the capacity/rotation speed of disk
drive is 1 type
In case of the capacity/rotation speed of disk
drive is n types
b) SATA Disk Drive
<Recommended number of Hot Spare Disk for SATA Disk Drive>
Conditions
In case the capacity/rotation speed of disk
drive is 1 type
In case of the capacity/rotation speed of disk
drive is n types
Recommended number of Hot Spare
Disk
1 per 24 HDD's
n types per 24 HDD's
Recommended number of Hot Spare
Disk
1 per 12 HDD's
n types per 12 HDD's
12
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