[Technical Notice] RAID vs Non-RAID System for Storing Surveillance Data

alexhon · Post by **alexhon** » September 20th, 2018, 9:59 pm

Article ID: GV39-12-3-27-t
Release Date: 3/27/2012

Applied to
RAID System

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.

1. Why We Recommend Using Non-RAID with GV-DVR / NVR
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-DVR / NVR’s free backup solution.

1.1 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.

1.2 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.

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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.

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1.3 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.

1.4 Backup Server: GeoVision’s Free Backup Mechanism
GV-DVR / NVR provides safe and free backup mechanism using Backup Server.

With Backup Server, the GV-DVR / NVR 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.

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For details on Backup Server, see 11.8 Backup Server, DVR User’s Manual.

2. Setting Up a RAID 5 System
If you do choose to use GV-DVR / NVR 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.

2.1 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.

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.

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Type the default username admin and password 0000 to log in the Web interface.

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In the left menu, click Quick Function and select Quick Create to start the Quick Setup.

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Use the Select RAID Level drop-down list to select RAID 5.

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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.

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- 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.
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.

3. 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:

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.
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.

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:

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Note: The maximum number of channels supported for GV-3008 / 4008 is 16 channels.

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Note: The data is obtained using H.264 codec.

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.

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