Avago Technologies 3ware SAS 9750-16i4e - Manual (Page 24)

Chapter 1. Introduction to the 3ware Command Line Interface
16 3ware SATA+SAS RAID Controller Card CLI Guide, Version 10.2
Hot Spare
A hot spare is a single drive, available online, so that a redundant unit is
automatically rebuilt without human intervention in case of drive failure.
Determining Which RAID Level to Use
The type of RAID unit (array) that you create depends on your needs. You
might want to maximize speed of access, total amount of storage, or
redundant protection of data. Each type of RAID unit offers a different blend
of these characteristics.
The following table summarizes RAID configuration types.
You can create one or more units, depending on the number of drives you
install. The following table provides possible configurations based on your
number of drives.
Table 2: RAID Configuration Types
RAID Type Description
RAID 0 Provides performance, but no fault tolerance.
RAID 1 Provides fault tolerance and a read speed advantage over non-
RAID disks.
RAID 5 Provides performance, fault tolerance, and high storage
efficiency. RAID 5 units can tolerate one drive failing before
losing data.
RAID 6 Provides very high fault tolerance with the ability to protect
against two consecutive drive failures. Performance and
efficiency increase with higher numbers of drives.
RAID 10 Provides a combination of striped and mirrored units for fault
tolerance and high performance.
RAID 50 Provides a combination of RAID 5 and RAID 0. RAID 50 provides
high fault tolerance and performance.
Single Disk Not a RAID type - but supported as a configuration.
Provides maximum disk capacity with no redundancy.
Table 3: Possible Configurations Based on Number of Drives
Number of
Drives
Possible RAID Configurations
1 Single disk
2 RAID 0 or RAID 1