2-Understanding RAID
Hot Swappable Disk support
Your RAIDBank4 has a built in protection circuit to support replacement of disk drives without having to shut down or reboot the RAID. In case of drive failure, the failed drive can be removed from the RAIDBank4 and replaced with a new drive without disrupting dataflow to the host computer.
Instant Availability/Background Initialization
RAID 0 and RAID 1 volume set can be used immediately after the creation, whereas RAID 3 and 5 volume sets must be initialized to generate parity information. RAIDBank4 features both foreground and background initialization modes for RAID 3 and RAID 5 volumes- In background mode, the initialization proceeds as a background task and the volume set is fully accessible for system reads and writes without requiring a reboot and waiting for the initialization completion. Furthermore, the RAID volume set is also protected against a single disk failure while initialing. Background initialization takes longer to complete and host disk access will be slower during the initialization process. Foreground Initialization must be completed before the volume set is ready for system accesses, but the RAID Initialization completes faster.
Online RAID Level and Stripe Size Migration
Users can migrate both the RAID level and stripe size of an existing volume set, while the RAIDBank4 is online and the volume set is in use. Online RAID level/stripe size migration can prove helpful during performance tuning activities as well as at the addition of physical disks to the RAIDBank4. For example, in a system using two drives in RAID level 1, you could add capacity and retain fault tolerance by adding one drive. With the addition of third disk, you have the option of adding this disk to your existing RAID logical drive by migrating from RAID level 1 to 5. The result would be parity fault tolerance and double the available capacity without taking the system offline.
Hot Spare Drives
A hot spare drive is an unused online available drive predesignated for replacing a failed disk drive. Any unused online available drive installed but not belonging to a RAID set can be defined as a hot spare drive. Hot spares permit you to replace failed drives automatically without powering down your RAIDBank4. When your RAIDBank4 detects a drive failure in a RAID 1,10,3 or 5 volume sets the system will automatically and transparently rebuild using any available hot spare drive(s). The volume set(s) will be reconfigured and rebuilt in background, while the RAIDBank4 continues to handle system requests. During the automatic rebuild process, system activity will continue as normal, but system performance will be reduced and the affected volume(s) will not be fault tolerant until the rebuild process is complete.
Hot-Swap Disk Rebuild
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