Raid 60 – Striping Of Double Parity - Promise Technology VTRAK E610f Product Manual

VTrak E-Class Product Manual
RAID 60 – Striping of Double Parity
RAID 60 combines both RAID 6 and RAID 0 features. Data is striped across
disks as in RAID 0, and it uses double distributed parity as in RAID 6. RAID 60
provides data reliability, good overall performance and supports larger volume
sizes.
Data
Stripes
Figure 6. RAID 60 Striping of Double Distributed Parity disk arrays
RAID 60 also provides very high reliability because data is still available even if
multiple disk drives fail (two in each axle). The greater the number of axles, the
greater the number of disk drives that can fail without the RAID 60 array going
offline.
RAID 60 arrays consist of eight or more physical drives.
Using a VTrak E610f/s or E310f/s subsystem expanded by four J300s
subsystems, your RAID 60 array supports up to 60 physical drives. See
"Configuring JBOD Expansion" on page 24 or page 30. However, Promise
recommends that you set aside a few physical drives as hot spares. See "Hot
Spare Drive(s)" on page 251.
Recommended applications: Accounting, financial, and database servers; any
application requiring very high availability.
RAID 60 Axles
When you create a RAID 60, you must specify the number of axles. An axle
refers to a single RAID 6 array that is striped with other RAID 6 arrays to make
RAID 60. An axle can have from 4 to 16 physical drives, depending on the
number of physical drives in the array.
The chart below shows RAID 60 arrays with 8 to 20 physical drives, the available
number of axles, and the resulting distribution of physical drives on each axle.
Double Distributed Parity
Disk Drives
240
Axle 1
Axle 2