RAID LEVELS

RAID (redundant array of independent disks) levels 0, 1, and 5 are typically implemented with SQL Server 2005.

RAID 0 : In RAID 0 Level data is stripped(shared) on disks, so it improve the write performance and read performance,data is splited in to 2 disks,if one disk is damaged the data will be lose

  

 

key points to remember for RAID level 0

• Minimum 2 disks.
• Excellent performance ( as blocks are striped ).
• No redundancy ( no mirror, no parity ).
• Don’t use this for any critical system.                       
  
  
  RAID 1 : In RAID 1 Level data is mirrored on disks,means same data is there on the 2 disks,read peroformance improves,write performance decrease,in this one disk is damaged then we can have data on mirrored disk.
  
  
  
  
  
  key points to remember for RAID level 1
  
  
• Minimum 2 disks.
• Good performance ( no striping. no parity ).
• Excellent redundancy ( as blocks are mirrored ).

RAID 5 : In RAID 5 Level we have parity check so data redundant is achieved with parity, if any disk will damaged the parity will gives the data,better performance than mirrored one,if strip member is missed read performance is decreased.

key points to remember for RAID level 5

• Minimum 3 disks.
• Good performance ( as blocks are striped ).
• Good redundancy ( distributed parity ).
• Best cost effective option providing both performance and redundancy. Use this for DB that is heavily read oriented. Write operations will be  slow.
  
  
  
  
  RAID 10 : In RAID 10 Level we can call it as RAID 1,0 (RAID 1 + RAID 0) in this data is stripped and that data is copied again on the disks, it provide best read-write performance
  
  
  
  
  
  
  
  key points to remember for RAID level 10
  
  
• Minimum 4 disks.
• This is also called as “stripe of mirrors”
• Excellent redundancy ( as blocks are mirrored )
• Excellent performance ( as blocks are striped )
• If you can afford the dollar, this is the BEST option for any mission critical applications (especially databases).