RAID and Subsystem Architectures
What type of Storage Device?
Can we use individual disks for our enterprise storage ?
Does an individual disk offer the features we require;
Resilience Scalability Performance
Data loss if drive Limited to individual Limited by individual
fails drive drive
Data loss if single Limited by maximum Limited by individual
(“Just a Bunch of
drive fails no of drives in JBOD drives
Protection against Large Arrays can Enhanced by caching
failure of an scale to many 100’s & striping
individual drive of drives
Just a Bunch of Disks (JBOD) storage:
JBODs are storage devices in which multiple disks are attached to a
common I/O bus and appear as individual attached devices to the
JBODs typically do not contain “intelligence.” If RAID is desired, it must
be implemented by software.
JBODs frequently use a Fibre Channel Arbitrated Loop as the array
backplane to which the disks are connected. Commonly there are two
loop ports provided, to allow a secondary loop to be configured, for
redundancy. Some FC disks allow both ports to be used at the same
time but most allow access through only one port at a time.