Raid 50 - Striping Of Distributed Parity - Promise Technology VTRAK E310f Product Manual

VTrak E-Class Product Manual
RAID 50 – Striping of Distributed Parity
RAID 50 combines both RAID 5 and RAID 0 features. Data is striped across
disks as in RAID 0, and it uses distributed parity as in RAID 5. RAID 50 provides
data reliability, good overall performance and supports larger volume sizes.
Data
Stripes
Figure 5. RAID 50 Striping of Distributed Parity disk arrays
RAID 50 also provides high reliability because data is still available even if
multiple disk drives fail (one in each axle). The greater the number of axles, the
greater the number of disk drives that can fail without the RAID 50 array going
offline.
RAID 50 arrays consist of six or more physical drives.
Using a VTrak E310f/s subsystem expanded by four J300s subsystems, your
RAID 50 array supports up to 60 physical drives. See "Configuring JBOD
Expansion" on page 18 or page 24. However, Promise recommends that you set
aside a few physical drives as hot spares. See "Hot Spare Drive(s)" on page 240.
Recommended applications: File and Application Servers, Transaction
Processing, Office applications with many users accessing small files.
RAID 50 Axles
When you create a RAID 50, you must specify the number of axles. An axle
refers to a single RAID 5 array that is striped with other RAID 5 arrays to make
RAID 50. An axle can have from 3 to 16 physical drives, depending on the
number of physical drives in the array.
Distributed Parity
Disk Drives
228
Axle 1
Axle 2