American Dynamics VideoEdge User Manual download pdf (Page 294)

Appendix A: Storage

278 VideoEdge NVR 4.4 Installation and User Manual

Direct Attached Storage

• This term is used to differentiate non-networked storage from networking systems such as NAS

and SAN.

• However, DAS cannot share information or space with other servers.

• DAS are usually connected via SCSI cables, along with a SCSI terminator.

• DAS can also be connected via eSATA or USB.

Storage Types

• JBOD – Just a Bunch of Disks

• RAID – Redu

ndant Array of Inexpensive Disks

JBOD

• The JBOD storage configuration is a group of disks without any RAID features, depending on

configuration in BIOS.

• In NVR systems, JBOD is rarely used with exte

rnal devices.

RAID

• An umbrella term for computer data storage schemes that distribute data across multiple disks

for increased input/output performance and/or better reliability.

• Since RAID systems use multiple disks, they are

often referred to as disk groups.

• Disk groups are also known as volumes or RAID arrays.

• There are different types of RAID configurations.

Some of the best known configurations are

RAID 0, 1, 5 and 1+0.

• Each configuration uses an approach to storage th

at can provide fault tolerance, additional

availability of data, redundancy, additional performance, or more than one of these factors.

Key RAID Concepts

• Mirroring – Duplicatin

g data to more than one disk.

• St

riping – Splitting data across more than one disk.

• Error Correction – S

toring redundant data so problems can be detected and possibly fixed.

Common RAID Types

• RAID 0 – Use

s striping to provide extra performance and capacity but does not provide data

protection (lack of mirroring or parity).

• RAID 1 – Us

es mirroring to provide 1:1 backup, which increases read performance or reliability

at the expense of capacity. This configuration is often used with databases due to better

transaction time and availability.

• RAID 1+0 (o

r 10) – is a mirrored data set (RAID 1) which is then striped (RAID 0), hence the

name “1+0”. A RAID 1+0 array requires a minimum of four drives – two mirrored drives to hold

one half of the striped data, plus another two mirrored drives to hold the other half of the data. In

LINUX, MD RAID 10 is a non-nested RAID type like RAID 1 that only requires a minimum of two

drives and may give read performance on the level of RAID 0.

• RAID 5 – Pre

serves against the loss of any one disk by combining the contents of three or more

disks. However, the total storage capacity is reduced by one disk. This configuration is often

used with VideoEdge because of RAID 5’s performance in situations where data transfers are

I/O intensive (“RAID 5 Performance Benchmarks” The Server Company).

1 2 ... 289 290 291 292 293 294 295 296 297 298 299 ... 373 374

Comments to this Manuals

No comments

American Dynamics VideoEdge User Manual Page 294

Comments to this Manuals

Related products and manuals for Networking American Dynamics VideoEdge