Generally speaking we recommend having both Wowza Streaming Engine and the VOD content on striped (RAID 0) drives. RAID 1 does not use striping but instead uses mirroring. From our Wowza Streaming Engine Specifications page.
Minimum recommended production hardware:
CPU: Single quad core, 3.00 GHz or better RAM: 4GB Disk: 2 or more in RAID 0 (striping) Network: 1Gbps Ethernet
High-load recommended production hardware:
CPU: Dual quad-core or a single hex-core, 3.00 GHz or better RAM: 16-32GB Disk: 2 or more in RAID 0 (striping) Network: 10Gbps Ethernet
More on our hardware specifications can be found below.
The reason we recommend both the server and your VOD content use RAID 0 is that not only can VOD content be accessed heavily but in some situations your log files may also write to the drive quickly.
You can install Wowza Streaming Engine in one location and have the VOD content in a different location.
You may want to reference our article on how to size your server for your environment.
If you are planning on doing live Adaptive Bitrate streaming then please take a look at our Transcoder benchmarks.