Netgear RN3138 Software Manual - Page 24

ReadyNAS OS 6.4 1. The first disk that you install is used for initial (unprotected) storage space. 2. The second disk that you install is reserved for data protection (parity information). 3. Installing additional disks increases your storage space. Note X-RAID reserves the capacity of one disk for data protection. The actual space reserved for data protection is distributed across all disks. Flex-RAID NETGEAR's Flex-RAID technology allows you to choose from among several industry-standard RAID levels: • JBOD. This most basic RAID level does not protect your data from loss if one of your drives fails. JBOD is available only on volumes consisting of a single hard disk. • RAID 0. RAID 0 distributes data across multiple disks, resulting in improved disk performance compared to systems that do not use RAID formatting. The total capacity of your storage system equals the capacity of the smallest of your disk drives times the number of disks. RAID 0 is available on volumes consisting of two or more hard disks. • RAID 1. This RAID level provides full redundancy of your data, because it duplicates data across multiple disks. Exactly the same data is stored on two or more disks at all times. RAID 1 protects your data from loss if one disk fails. The total capacity of your storage system equals the capacity of your smallest disk. • RAID 5. This RAID level also provides data redundancy, but it requires at least three disks. RAID 5 uses the capacity of one disk to protect you from data loss if one disk fails. Your data is distributed across multiple disks to improve disk performance. The total capacity of your storage system equals the capacity of all your disks minus the capacity of one disk. It is supported on systems with at least four drive bays. • RAID 6. This RAID level provides recovery from the loss of two disks. Your data is distributed across multiple disks to improve disk performance. The total capacity of your storage system equals the capacity of all your disks minus the capacity of two disks. It is supported on systems with at least four drive bays. • RAID 10 (or 1+0). This RAID level uses both RAID 1 and RAID 0 technology. First, your data is duplicated so that exactly the same data is stored on two or more disks. Then the data is distributed across additional disks to improve disk performance. It is supported on systems with at least four drive bays. • RAID 50 (or 5+0). This RAID level uses both RAID 5 and RAID 0 technology. First, a disk is used to provide redundancy. Then your data is distributed across multiple disks to improve disk performance. A minimum of six disks are required. The total capacity of your storage system equals the capacity of all your disks minus the capacity of two disks. • RAID 60 (or 6+0). This RAID level uses both RAID 6 and RAID 0 technology. First, two disks are used to provide redundancy. Then your data is distributed across multiple disks to improve disk performance. A minimum of eight disks are required. The total capacity of your storage system equals the capacity of all of your disks minus the capacity of four disks. The Flex-RAID levels that you can select depend on the number of disks included in the volume. The following table describes the Flex-RAID levels that are available for a given number of disks. It also indicates whether adding a disk for data protection is possible for each configuration. Volume Configuration 24