Transcript Storage

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 iSCSI 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
 In this architecture, we call “Direct-attached storage” (DAS).
 It is simple to install and has high security.
However,
 If the storage requirement is increased, it is difficult to be expanded
more hard disk.
 It is not easy to share the stored video to other people.
Storage with Internet
Internet
NVR Server
Storage device
Storage device
Store the recording video
Request the recording video to playback from server
NVR Workstation
 In this architecture, we call “Network-attached storage ” (NAS)
 It can expand to add other storage devices flexibly.
 Ease to share stored video data in storage device.
However,
 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
Storage area network (SAN).
Because storage devices are independent from servers, SAN increases
the storage space usability and provide efficient sharing system.
 It provides high speed of connection in SAN system.
Ex, Fibre Channel (Optical Fiber) and iSCSI (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
iSCSI
• iSCSI is based on Ethernet network architecture and uses exclusive
communication over IP networks in SAN system to achieve high
speed connection.
• iSCSI also need specific equipment to support iSCSI protocol,
including the Ethernet card of server/storage devices and the switch.
• In iSCSI needs to use the exclusive communication to define the
transmitter (iSCSI initiator)and the receiver (iSCSI Target ) for
server and storage devices at first to send information.
Transmitter
Receiver
Storage
Device
Switch
NVR server
iSCSI Card
Switch
NVR server
Ethernet
iSCSI
Ethernet
Switch
Storage
Device
iSCSI 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 disk1, data B to disk2
and data C to disk1…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 disk1 and disk2 in
the same time. Data B to disk1 and
disk2 in the same time.
• Disk 2 is the backup of disk1.
While some data in disk1 have
damage, we still can find data on
disk2.
Data A
Data B
Data C
Data D
Storage
Data A
Data A
Data B
Data B
Data C
Data C
Data D
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 disk1.
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)x24(hour/day)x60(min/hour)x60(sec/min)
= 432,000 (sec)
Storage size= 1Mbps x 432,000 (sec) / 8
= 432,000M (bit) / 8
= 54,000M (byte)
= 54G (byte)