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IOMEGA STORAGE PROVISIONING AND RAID MIGRATION CONFIGURATION GUIDE
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RAID 0: this RAID level distributes data across multiple disks in a way that gives improved speed at any given
instance. If one disk fails, however, all the data on the array will be lost, as there is neither parity nor mirroring.
RAID 0 is non-redundant. A RAID 0 array requires a minimum of two drives.
RAID 1: this RAID level mirrors the contents of the disks, making a form of 1:1 ratio real-time backup. The contents
of each disk in the array are identical to that of every other disk in the array. A RAID 1 array requires a minimum of
two drives.
RAID 5: this RAID level combines three or more disks in a way that protects data against loss of any one disk.
Fault tolerance is achieved by calculating parity and distributing parity to all disks. Distributed parity requires all
drives but one to be present to operate; drive failure requires replacement, but the array is not destroyed by a
single drive failure. Upon drive failure, any subsequent reads can be calculated from the distributed parity, such
that the drive failure is masked from the end user. The array will have data loss in the event of a second drive
failure and is vulnerable until the data that was on the failed drive is rebuilt onto a replacement drive. A single
drive failure in the set will result in reduced performance of the entire set, until the failed drive has been replaced
and rebuilt.
RAID 6: this RAID level combines four or more disks in a way that protects data against loss of any two disks.
Fault tolerance is achieved by calculating dual parity and distributing them to all disks. Distributed dual parity
requires all drives but two to be present to operate.
RAID 10 (or 1+0): this RAID type is a mirrored data set (RAID 1) which is then striped (RAID 0), hence the “10”
name. RAID 10 normally requires a minimum of four drives: two mirrored drives to hold half of the striped data,
plus another two mirrored for the other half of the data.
CIFS: Common Internet File System, also known as Server Message Block (SMB). It operates as an application-
layer network protocol mainly used to provide shared access to files, printers, serial ports, and miscellaneous
communications between nodes on a network. It also provides an authenticated inter-process communication
mechanism. Most usage of CIFS involves computers running Microsoft Windows.
Network File System (NFS): A distributed file system providing transparent access to remote file systems.
NFS allows all network systems to share a single copy of a directory.
iSCSI: Internet Small Computer System Interface. This is a protocol for sending SCSI packets over a TCP/IP
network.
SCSI: Small Computer System Interface. Standard set of protocols for host computers communicating with
attached peripherals.
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