RAID
What are JBOD Disk Arrays?
JBOD Disk Arrays are a collection of disks that are presented as a single logical unit without any RAID functionality.
What does JBOD stand for?
Just a Bunch of Disks
What is JBOD?
Just a bunch of disks, a disk array without RAID.
What is RAID?
A disk sub-system that combines multiple physical disks into a single logical storage unit.
What is RAID?
A disk subsystem that combines multiple disks into one unit.
What is the overhead for RAID 1?
Overhead is 1/n, where n is the number of disks.
What is the overhead of RAID 5?
RAID 5 has an overhead of one disk in the set for parity information.
What is RAID 5?
RAID 5 provides increased performance for read operations and requires a minimum of three disks.
Which RAID level provides both fault tolerance and performance improvement?
RAID 5.
What is operating system RAID?
RAID using RAID features within the OS.
What is software RAID?
RAID using a driver and system CPU.
What is hardware RAID?
RAID using a special controller card.
What is the purpose of RAID?
To improve performance and provide fault tolerance.
What can you do if one drive fails in a JBOD configuration?
Use disk recovery tools to recover data from the remaining disks
What is the overhead percentage for a RAID 5 set with 3 disks?
A RAID 5 set with 3 disks has 33% overhead.
What is JBOD?
A configuration that places multiple disks in a single logical storage unit.
What is RAID 0?
A stripe set that improves performance but has no fault tolerance.
What happens if one disk fails in RAID 0?
All data is lost.
What is the requirement for disk sizes in RAID configurations?
In RAID configurations, the disk sizes must be equal. The resulting volume will be limited to the smallest disk if disks are of different sizes.
What is the overhead for RAID 0?
No overhead, all disk space is available for data.
Is RAID a substitute for regular backups?
No, configuring RAID is not a substitute for regular backups.
What is the overhead percentage for a RAID 5 set with 4 disks?
A RAID 5 set with 4 disks has 25% overhead.
What is the overhead percentage for a RAID 5 set with 5 disks?
A RAID 5 set with 5 disks has 20% overhead.
What is RAID 1?
A mirrored volume that provides fault tolerance but no performance improvement.
What is RAID 5?
A volume that combines striping with distributed parity for fault tolerance.
What are the advantages of operating system RAID?
Better performance than software RAID.
What are the advantages of hardware RAID?
Better performance, more reliable.
What does JBOD do?
Configures multiple disks into a single logical storage unit
What happens if one disk fails in RAID 5?
Data can be recovered using parity information.
How is data saved in a JBOD configuration?
Data is saved to one or more disks
What happens if one disk fails in RAID 1?
Data is still present on another disk.
What are the characteristics of hardware RAID?
Expensive, better performance, more reliable.
How many disks are required for RAID 5?
Minimum of three disks.
How many disks are required for RAID 0?
Minimum of two disks.
How many disks are required for RAID 1?
Minimum of two disks.
Are there any performance or fault tolerance benefits with JBOD?
No
Is JBOD a RAID configuration?
No
What is the overhead for RAID 5?
No overhead for storing parity information.
Which RAID level provides the best performance?
RAID 0.
What is the most expensive fault tolerant system?
RAID 1.
Which RAID level provides the most fault tolerance?
RAID 1.
What is RAID 10?
RAID 10 (stripe of mirrors) stripes data across mirrored pairs and provides fault tolerance for a single disk failure.
What does RAID 10 provide?
RAID 10 provides redundancy and performance.
How many disks are required for RAID 10?
RAID 10 requires a minimum of four disks.
What is the capacity usage of RAID 10?
RAID 10 uses 50% of the total raw capacity of the drives due to mirroring.
What are the characteristics of software RAID?
Slowest form of RAID, some controller cards support it.
What are the disadvantages of software RAID?
Slowest form of RAID.
What are some combined levels of RAID?
Some combined levels of RAID include RAID 0+1, RAID 1+0 (RAID 10), RAID 5+0, and RAID 5+1.
What does spanning mean in the context of JBOD?
The volume spans multiple physical disks
What are the characteristics of operating system RAID?
Uses system CPU, better performance than software RAID.
How is operating system RAID implemented?
Using RAID features within the OS.
How is software RAID implemented?
Using a driver and system CPU.
How is hardware RAID implemented?
Using a special controller card.
Can disks used in a JBOD configuration be of different sizes?
Yes
Does JBOD use the entire space available on all disks for data storage?
Yes
