Storage Networking Storage Trends Storage grows 20 150year

Storage Networking

Storage Trends • Storage grows 20 -150%/year, gets more complicated • It’s necessary to pool storage for flexibility • Intelligent storage is necessary to reduce administrative costs – simplify and automate management • Continuous availability is required

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

RAID • • RAID 0 – Striping RAID 1 – Mirrored Volumes RAID 0+1 – Mirror of stripes RAID 3 – Byte-level striping with Parity disk RAID 4 – Block-level striping with Parity disk RAID 5 – Striping with distributed Parity RAID 1+0 -Stripe of mirrors RAID 6 – Double striped to support 2 drive failures

Software RAID • Volume Management 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 environments

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

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

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

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

i. SCSI • An alternative technology – 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

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