System Optimization Storage Introduction Storage TypesDASNASSAN The purposes

System Optimization Storage

Introduction Storage • Types-DAS/NAS/SAN • The purposes of different RAID types. • How to calculate the storage size for video recording?

Agenda • The position of storage in the procedure of video surveillance system. • Common types of storage. • Fibre Channel and i. SCSI in SAN. • RAID • Storage Size Calculation

The Procedure of Video Surveillance System NVR Capture Video Compress Data Decompress Data for live View Transmit Data Recording video Storage Decompress Data for Playback

Basic Storage NVR Hard Disk Store the recording video l In this architecture, we call “Direct-attached storage” (DAS). l It is simple to install and has high security. However, l If the storage requirement is increased, it is difficult to be expanded more hard disk. l It is not easy to share the stored video to other people.

Storage with Internet NVR Server Internet Storage device Store the recording video Request the recording video to playback from server NVR Workstation l In this architecture, we call “Network-attached storage ” (NAS) l It can expand to add other storage devices flexibly. l Ease to share stored video data in storage device. However, l Network bandwidth is unstable might cause the video lag.

Independent network of storage system Storage Device NVR server NVR Workstation Switch Internet NVR server Switch NVR Workstation NVR server Storage Device SAN Store the recording video Request the recording video to playback from server l. Storage area network (SAN). l. Because storage devices are independent from servers, SAN increases the storage space usability and provide efficient sharing system. l It provides high speed of connection in SAN system. Ex, Fibre Channel (Optical Fiber) and i. SCSI (Ethernet) technologies.

Fibre Channel • Fibre Channel means the connection between NVR server、 switch and storage devices in SAN system use “Optical Fiber”. • The cables and equipments are special for optical fiber. • The maximum data rate of fibre channel is up to 1600 MByte/s. • The maximum distance of optical fiber cable is up to 50 km. Storage Device NVR server NVR Workstation Switch Internet Storage Device NVR server Switch NVR Workstation SAN Ethernet NVR server Optical fiber

i. SCSI • i. SCSI is based on Ethernet network architecture and uses exclusive communication over IP networks in SAN system to achieve high speed connection. • i. SCSI also need specific equipment to support i. SCSI protocol, including the Ethernet card of server/storage devices and the switch. • In i. SCSI needs to use the exclusive communication to define the transmitter (i. SCSI initiator)and the receiver (i. SCSI Target ) for server and storage devices at first to send information. Transmitter Receiver Storage Device Switch NVR server i. SCSI Card Switch NVR server Ethernet i. SCSI Ethernet Switch Storage Device i. SCSI Card

How to advance storage function? We want to • Increase the speed of storage. • Backup the storage data. RAID (Redundant Array of Independent Disks)

RAID • RAID uses multiple independent disk drives to increase storage functions. • The purposes of different RAID types are – Speed up the transmission of data storage. – Backup the storage data. – Recovery the storage data while one disk drive has damage situation.

Increase the speed of storage • It transmits the sequence sections of one data to two disks separately. • Ex, data A to disk 1, data B to disk 2 and data C to disk 1…etc. • Thus, the speed of storage data shall be the half than normal type. Data A Data B Data C Data D Storage Data A Data B Data C Data D Disk 1 Disk 2

Backup • It transmits the same section of data to two disks synchronously. • Ex: Data A to disk 1 and disk 2 in the same time. Data B to disk 1 and disk 2 in the same time. • Disk 2 is the backup of disk 1. While some data in disk 1 have damage, we still can find data on disk 2. Data A Data B Data C Data D Storage Data A Data B Data C Data D Disk 1 Disk 2

Recovery Data A Data B Data C Data D Data E Data F Storage Data A Data B Encode(A, B) Data C Data D Encode (C, D) Data E Data F Encode (E, F) Disk 2 Disk 3 Disk 1 • It transmits sequence sections of a data to two disks and also store the encoded data of transmitted sections to third disk. • If disk 1 has error or damage situation, we can replace a new disk and use the encode data in third disk to recovery the original data in disk 1.

Storage Size Calculation

Storage size calculation Storage size (bytes) = bitrate* x Time (sec) / 8** * bitrate = video data size (bit)/sec ** bit byte (8 bits = 1 bytes)

Storage size calculation Ex: If the 1 Mbps video from one camera has to be stored in NVR server for 5 days, how big storage space do I need? A: Time (sec)=5(day)x 24(hour/day)x 60(min/hour)x 60(sec/min) = 432, 000 (sec) Storage size= 1 Mbps x 432, 000 (sec) / 8 = 432, 000 M (bit) / 8 = 54, 000 M (byte) = 54 G (byte)