Why do we prefer RAID 5 than RAID 1 ?

RAID 1 is basically mirroring which keeps the two copies of same data on two disks. RAID 5 uses distributed parity which is tolerate single disk failure at a time.

Failure chances of Servers is less in Raid 5 as comapre to Raid 1. 

RAID 1 is basically mirroring which keeps the two copies of same data on two disks. This will lead us to a situation of having only half of the total storage usable for saving data.

RAID 5 uses distributed parity which is tolerate single disk failure at a time. The storage efficiency as well as performance are comparitively higher than RAID 1.

RAID 1  basically implements Mirroring.

The main disadvantage of RAID 1 is that that the effective storage capacity is only half of the total drive capacity because all data get written twice.

On the other hand  RAID 5 is a good all-round system that combines efficient storage with excellent security and decent performance. It is ideal for file and application servers that have a limited number of data drives.

• Read data transactions are very fast while write transactions are a bit slow due to the parity calculation.
• If a drive fails, you still have access to all data, even while the failed drive is being replaced and the storage controller rebuilds the data on the new drive.(The biggest advantage)

In Raid 5 If a drive fails, you still have access to all data, even while the failed drive is being replaced and the storage controller rebuilds the data on the new drive

Because RAID 5 gives performance since its blocks are striped and also its gives redundancy since it got distributed parity. 

In genrl we can say that for better performance and data protection we use raid 5 over raid 1

RAID 1 is a simple mirror arrangement in which two (or more) same physical drives allow for redundancy tolerance and fault. RAID 5 provides fault tolerance, but distributes data by interleaving it across multiple disks.

RAID 1 Key Feature VS RAID 5 Key Feature

Mirroring Striping with parity

Redundancy and fault tolerance                          Fault tolerance by Parity Info.

Slow Read and Write                                           Fast Read and Write

Minimum 2 Disk                                                    Minimum 3 Disk