AJA io hd, Installation And Operation Manual

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Io HD Installation and Operation Manual — System Requirements
Striping divides a logical drive into data blocks, or stripes, that are distributed across
an array of physical drives. Striping a set of disks improves storage performance
because each drive operates concurrently. However, striping alone, known as RAID
level 0, offers no data protection.
Mirroring involves writing identical copies of all data to a pair of physical drives. This
results in very high data reliability: If one drive fails, the data is still available on the
remaining disk drive. However, it also results in a storage efficiency of only 50 percent,
because two physical drives are required to achieve a single drive’s capacity. Mirroring
alone is known as RAID level 1.
Parity provides data protection without requiring complete duplication of the drive
contents. In the event of a drive failure, parity information can be used with data on
surviving drives to reconstruct the contents of a failed drive. Parity data can be stored
on a dedicated drive, as in RAID 3, or distributed across an array of drives, as in
RAID 5. Parity provides much greater storage efficiency than mirroring—up to 85
percent for a set of seven drives.
Software For Striping
AJA recommends the Disk Utility software provided by Apple with OS X for creating
and striping RAIDs, including 3rd-party disk arrays and Xserve RAIDs. This
application is very easy to use and has been tested to work well. The utility can be
found in
Macintosh HD/Applications/Utilities, where “Macintosh HD” is the name of
the system drive.
Xserve RAID
Xserve RAID is designed for non-stop operation. Redundant hot-swap power and
cooling modules allow the system to keep functioning even if one module fails. A
high-availability architecture and dual independent RAID controllers support RAID
levels 0, 1, 3, 5, and 0+1. In addition, Xserve RAID supports hybrid RAID levels 10,
30, and 50 when used in conjunction with host-based software RAID. Remote Xserve
RAID management capabilities are provided via Apple’s Java-based RAID Admin
application.
Note: When creating and striping an Xserve RAID for Io HD using the Apple Disk
Utility provided with OS X, use RAID 50 : in other words, the internal Xserve RAID
drives are set up as RAID 5; the Xserve RAID then shows up in Disk Utility as two
drives (regardless of the number of internal drives) which must be configured together
as RAID 0. Apple calls this configuration “RAID 50.”
Storage capacity
No matter which storage system you choose, pick one that can scale to meet your
needs over time. Ideally, you should be able to increase storage capacity or switch to a
RAID level offering increased data protection in the future. Balance current and
future storage needs with your budget and choose accordingly.