1. Storage Networking

2. Storage Trends Storage growth Need for storage flexibility
Simplify and automate management
Continuous availability is required

3. Storage considerations
Capacity
Performance
Scalability
Availability and Reliability
Backup and recovery requirements
Support/staff needs
Budget

4. RAID Consolidate multiple physical disks into a logical grouping
Designed for fault tolerance and performance improvement
Can be implemented in H/W or S/W
Several RAID levels exist

5. Hardware RAID Volume Management performed by RAID controller
Parity computation performed by the RAID controller – decreases server overhead
Dedicated cache memory improves server performance

6. Software RAID Performed by the server O/S
Parity computation performed by the server – increased overhead
RAID performance depends on the server performance and CPU load
For simple environments with lower performance and availability requirements

7. Simple levels of RAID RAID 0 – Striping RAID 1 – Mirrored Volumes
RAID 2 – Bit-level striping with parity distributed to one or more disks
RAID 3 – Byte-level striping with dedicated parity disk
RAID 4 – Block-level striping with dedicated parity disk
RAID 5 – Block-level striping with distributed parity
RAID 6 – Block-level striping with distributed double parity

8. Nested RAID RAID 0+1: striped sets in a mirrored set
RAID 10 (or RAID 1+0): mirrored sets in a striped set
RAID 5+1: mirrored striped set with distributed parity (also known as RAID 53)
RAID 5+0: striped set of RAID-5 sets

9. Block-level vs File-level access
File systems 2 views:
1. Data representation to users/applications (hierarchical view)
2. Storage organization (data structure)
Block-level access: write/read blocks; master/slave relationship
File-level access: using file names; client/server relationship

10. DAS
Block-level access
File system is on the server
SCSI protocol

11. DAS

12. NAS
File-level access to the outside; block-level to the storage subsystem
File system is on the NAS device
Clients
IP Network
File Protocol: SMB/CIFS, NFS, etc.
Servers

13. NAS

14. SAN Block-level access File system is on the server Storage Area
Network
SCSI over Fibre Channel
Servers

15. SAN

16. SAN
Traditional SANs used Fibre Channel protocol and storage technology to connect SAN at gigabit speeds
SCSI commands transmitted over FCP
Expensive
Requires dedicated network equipment/architecture

17. IP Storage As an alternative, existing IP infrastructure can be used
FCIP, iFC protocols allow Fibre Channel devices to be connected over IP networks
iSCSI allows SCSI commands to be encapsulated to be transferred through an IP network

18. iSCSI Allows SAN utilize TCP/IP for block-level data transfer
Transport for SCSI commands
Existing networks (routers/switches) can be utilized – no need for special equipment
With current network technologies supporting gigabit speeds, comparable to FC in speed

22. NAS-SAN Integration

23. Distributed File Systems
SMB/CIFS; Samba (Windows-based systems)
NFS (Unix-based)
AFS (Unix)
AFP (MAC)
NCP (Netware)