RAID vs Non-RAID System for Storing Surveillance Data

1. RAID vs Non-RAID System
for Storing Surveillance Data
Article ID: GV39-12-3-27-t
Release Date: 3/27/2012
1. Introduction
Although RAID has become increasingly popular in recent years, this document explains why
using non-RAID systems with regular backup is more practical for storing surveillance data. If
you do choose to use RAID though, we recommend building RAID 5 using hardware RAID.
2. Why We Recommend Using Non-RAID with GV-System
There are several drawbacks of using RAID systems to store surveillance data. RAID reduces
space efficiency and does not provide sufficient data protection. RAID does not completely
substitute regular backup and we suggest using non-RAID systems with GV-System’s free
backup solution.
Losing All Data When Fault Tolerance Exceeded
When recording video for surveillance purposes, hard disks tend to have a high failure rate
because they are constantly reading and writing data. Multiple hard drive failure happens from
time to time and in a RAID system, data on all hard disks would be lost if the fault tolerance of
the RAID level is exceeded.
All data is lost if
• Any of the hard disks fail in RAID 0
• More than 1 hard disk fails in RAID 1 with two hard drives
• More than 1 hard disk fails in RAID 5
In a non-RAID system, data in all other hard disks will be intact and only the data on the failed
hard disk will be lost.
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2. Reduced Space Efficiency When Using RAID 1 or Above
Storing recorded video often requires a large amount of storage space. In RAID 1 or above,
the amount of space you can utilize is reduced because data is replicated.
Min # of HDD Storage Capacity Examples
required
Non-RAID 1 Full storage capacity 1 TB HDD x 2 = 2 TB capacity
RAID 0 2 Full storage capacity 1 TB HDD x 2 = 2 TB capacity
RAID 1 2 50% storage capacity 1 TB HDD x 2 = 1 TB capacity
1 TB HDD x 4 = 2 TB capacity
RAID 5 3 # of HDD – 1 HDD 1 TB HDD x 3 = 2 TB capacity
1 TB HDD x 4 = 3 TB capacity
With non-RAID or RAID 0, the capacity of all hard disks can be utilized. However, in RAID 1,
an identical copy of the data is stored in each hard disk, so the usable capacity will be reduced
by half. In RAID 5, the capacity of 1 hard drive is used to store the redundant data, so the
storage capacity is reduced to the number of hard drives minus 1 hard drive. The lower space
efficiency in RAID 1 or above is especially uneconomical at a time of soaring hard disk prices.
Non-RAID RAID 1
A E A A
B F B
= B
C G C C
D H D D
Disk 1 Disk 2 Disk 1 Disk 2
(500 GB) (500 GB) (500 GB) (500 GB)
Total capacity: 1000 GB Total capacity: 500 GB
Read and Write Speed Comparison
Below we rank non-RAID, RAID 0, RAID 1 and RAID 5 in the order of fastest to slowest read
and write speed.
RAID 0 > Non-RAID > RAID 5 > RAID 1
Some people prefer RAID for faster read and write speed, but the data access speed of a
non-RAID system is actually almost as fast as that of RAID 0 and slightly better than RAID 5.
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3. Backup Server: GeoVision’s Free Backup Mechanism
GV-System provides safe and free backup mechanism using Backup Server.
With Backup Server, the GV-System can back up recorded files to the storage system both
locally or over the Internet to multiple drives. When Backup Server is enabled, a copy of
recorded files will automatically be backed up to the storage system.
The Backup Server supports any storage system protocol which can add itself to Windows
and be formatted by Windows Disk Management. The following diagram shows the possible
types of storage systems the Backup Server can support.
Network Storage Local Storage
iSCSI GV-System eSATA
NAS USB
+
Thecus 5200N Internal Hard Drive
Backup Server
For details on Backup Server, see 11.9 Backup Server, DVR User’s Manual on the
Surveillance System Software DVD.
3. Setting Up a RAID 5 System
If you do choose to use GV-System with a RAID system, building a RAID 5 system provides
the following advantages:
• More efficient storage capacity compared with RAID 1 or above
• Data access speed close to non-RAID systems
• Protection against 1 hard drive failure
It is also recommended to use a GeoVision or third-party RAID Controller Card for better
performance instead of using software RAID.
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4. Setting Up RAID System
Below is an example of how to set up a RAID 5 system using GeoVision’s RAID Controller
Card. The optional RAID Controller Card can be purchased to support hardware RAID
function.
Note: Different RAID Controller Cards will have different settings. Refer to the
documentation of your RAID Controller Card for proper setup.
1. After installing the RAID Configuration Utility from the supplied software CD, select
Controller #01 (PCI) and click the Launch Browser button to access the Web interface.
2. Type the default username admin and password 0000 to log in the Web interface.
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5. 3. In the left menu, click Quick Function and select Quick Create to start the Quick Setup.
4. Use the Select RAID Level drop-down list to select RAID 5.
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6. 5. If the capacity of a single RAID group exceeds 2 TB, select 64bit LBA or 4K Block in the
Greater Two TB Volume Support drop-down list.
64bit LBA: 64-bit LBA with 512 sectors (blocks). The option works on different OS
that supports 16 bytes CDB.
4K Block: 32-bit LBA with 4K sectors (blocks). It changes the sector size from
default 512 bytes to 4K bytes. The size of a single file cannot exceed 16 TB.
Tip: Select 64 bit LBA if you are using Windows XP and select 4K block if you are using
Windows 7 or Windows Server 2008.
6. Select Confirm The Operation and click the Submit button to begin building the RAID
system.
To see the status or the progress of the RAID creation, click Information in the left menu and
select RAID Set Hierarchy.
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7. 4. FAQ
Q1: What’s the difference between using the built-in RAID function on the motherboard
and using a RAID controller card?
Some motherboards come with built-in software RAID where the RAID function is performed
by the CPU of the PC. Although no additional hardware is required, software RAID tends to
drain system resources and decrease the CPU’s efficiency. On the other hand, hardware
RAID uses a RAID card to process the data externally and does not add burden to the PC.
Q2: Can I build a RAID group using hard disks from different brands?
You can build a RAID group using hard disks from different brands, but you need to consider
two factors:
(a) Storage size: When using hard disk with different storage capacity, the storage capacity
may be based on the smallest hard disk. For example, if you create a RAID 1 using one 1
TB hard disk and one 500 GB hard disk, the space you can utilize will be 500 GB.
(b) Rotational speed: Data access performance will be affected if hard disks of different
rotational speed are used.
Consequently, creating a RAID group using hard disks of different sizes and rotational speed
is not recommended.
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8. Q3: Can I build a RAID system on GV-Hot Swap DVR System?
Building a RAID system on GV-Hot Swap DVR System is not recommended, but if you decide
to do so, creating a RAID 5 system will provide a fault tolerance of one hard disk and better
space efficiency compared to other RAID levels. You must purchase the accessory GV-RAID
Controller Card and have it installed before the system is shipped to you.
Note: GV-RAID Controller Card only supports 8 / 4-bay models.
The maximum number of channels each hard disk can record is listed below:
Analog Cameras
Maximum Number of Channels per HDD
Resolution Frame Rate Bit Rate
(8 / 4-Bay Models)
CIF 30 fps 0.26 Mbps 32 Channels
D1 (SW) 15 fps 0.53 Mbps 32 Channels
D1 (HW) 30 fps 2.6 Mbps 16 Channels
Note: The maximum number of channels supported for GV-3008 / 4008 is 16 channels.
IP Cameras
Maximum Number of Channels per HDD
Resolution Frame Rate Bit Rate
(8 / 4-Bay Models)
1.3 MP 30 fps 3.7 Mbps 28 Channels
2.0 MP 30 fps 6.7 Mbps 16 Channels
3.0 MP 20 fps 5.7 Mbps 24 Channels
Note: The data is obtained using H.264 codec.
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9. Q4: Can I store data recorded by GV-Recording Server on a RAID system?
Storing data recorded by GV-Recording Server on a RAID system is not recommended, but if
you decide to do so, you can choose a third-party RAID controller card or use GV-Hot Swap
Recording Server System with the optional GV-RAID Controller Card. You must purchase the
accessory GV-RAID Controller Card and have it installed before the system is shipped to you.
Note: GV-RAID Controller Card only supports 8 / 4-bay models.
The maximum number of channels each hard disk can record is listed below.
GV-Hot Swap Recording Server System with GV-RAID Controller Card
Maximum Number of Channels per HDD
Resolution Frame Rate Bit Rate
(8 / 4-Bay Models)
1.3 MP 30 fps 3.7 Mbps 28 Channels
2.0 MP 30 fps 6.7 Mbps 16 Channels
3.0 MP 20 fps 5.7 Mbps 24 Channels
GV-Recording Server (Software only)
Resolution Frame Rate Bit Rate Maximum Number of Channels per HDD
1.3 MP 30 fps 3.7 Mbps 32 Channels
2.0 MP 30 fps 6.7 Mbps 21 Channels
3.0 MP 20 fps 5.7 Mbps 32 Channels
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