RAID

Question 1

RAID

Answer 1

Redundant Array of Independent Disks

Question 2

RAID 0

Answer 2

Striping
File blocks are split between
2 or more physical drives
– Most extreme performance possible
– Data written quickly
– Best if doing multiple/frequent backups as the raid array will completely break if one drive fails
– Ideal for live streaming, iptv, vod edge server
No redundancy
– A drive failure breaks the array
– Raid 0 is zero redundancy
– Not ideal for essential tasks

Question 3

RAID 1

Answer 3

Mirroring
File blocks are duplicated between
two or more physical drives
High disk utilization
– Every file is duplicated
– Required disk space is doubled
High redundancy
– Drive failure does not affect data availability
Advantages- ideal for mission critical storage (Accounting), smaller servers, fault tolerant w/ easy data recovery
Disadvantages - half storage cpapacity of total drive storage, software-based raid 1 does not always allow for hotswap (downtime or power down is requited to replave drive)

Question 4

RAID 5

Answer 4

Striping with parity
File blocks are striped
– Along with a parity block
– Requires at least 3 disks
Efficient use of disk space
– Files aren’t duplicated, but space
is still used for parity
High redundancy
– Drive is available after a failure
– Parity calculation may affect
performance
Advantages - excellent read performance, fault tolerant (allows for one failure without penalty, second drive failure forces raid rebuild)
Disadvantages - drive failures affect the enitre array even if it still functions, write is relatively slow due to parity that requires use of all drives

Question 5

RAID 10

Answer 5

The speed of striping, the
redundancy of mirrors
Need at least 4 drives
Common for highly used servers (lots of write actions)
Advantages - fault tolerant (fast recovery time), high read/write performance, array can be saved up to 3 failures depending on which drives have failed (if two drives holding the same data fails at the same time, the array will fail. however this is highly unlikely to happen)
disadvantages - lower usable capacity (half of the storage is just mirroring), EXPENSIVE