SQL Server RAID Storage I have been reading about recommended SQL Server storage and RAID 5 or RAID 10 controllers have been recommended.

On my existing Database server I can see 4 Storage controllers under Device Manager.
They are listed as:


LSI Adaper (*2)
VMWare PVSCSI Controller (*2)


Are these an alternative to RAID? Or should I be using RAID for SQL Server?
"Storage Controllers" &lt;> "RAID".  RAID is a configuration, not hardware.  

For example, RAID 5 refers to having at least 3 physical disks typically attached to a disk controller such that stripes of data and parity are written across all three disks any time data is written to the array.  If you had 3 x 76GB drives, a RAID-5 array would have 76 x 2 = 152GB of usable capacity since 1/3 of the total space is dedicated to parity data.  The parity data is used to calculate the missing data if any one of the drives in the array fails. The RAID array looks like a single physical disk to the operating system installed on the machine.

For SQL Server, RAID-5 is typically counter-indicated since calculating and writing the parity information causes writes to be slower than with RAID-10.  RAID-10 consists of at least 4 drives, 2 mirrored sets of RAID-0 arrays.  Since RAID-10 does not have to calculate parity data, it is typically faster than RAID 5, and since the array is mirrored, it can survive up to 2 simultaneous drive failures.  However, capacity of a RAID 10 array is smaller than a RAID 5 array consisting of the same number and size of drives.

To answer your question, no, these controllers do not by themselves mean you have any RAID at all in the system.  Since the server you are looking at is a virtual machine, you would need to find out from the system administrator of the physical host machine what kind of storage it has.