4 November-12 November
This is what i have done with SAN research until now.
The information of this research from references "will be written down when i finish ".
The research duration end by 16 of October..
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Storage area network is type of network which a group of servers is connected via
high speed cable with storage unit “Disk array”.
The main
purpose of this Network is to keep the data storage safely from users’ PCs or servers with separated
storage units, so any damages happen to the servers
will not affect on the data.
The below figure show simple of SAN:
Advantages
of SAN,
-High speed data transmission by
using Fiber Optic Channel.
-Central storage units allow many
servers to access at the same time.
-Secured technique for saving data,
due to data isolated far of servers damages risk.
- Minimize the number of servers used, instead of
assigning file server for each network.
- Easy data access with time saved.
-This technology allows connecting
servers with different OS such as, Red hat, Win…etc.
Storage area
network Layers,
SAN consist
of 3 layers which are:
-Host layer, user’s PC or servers
-Fiber layer, the middle layer which connects the PCs, servers
with storage unites via routers, switches or hubs.
-Storage layer, which is the storage
unit.
Techniques
of SAN:
There are so
many techniques of SAN in here some of that techniques.
1- Small Computer
System Interface SCSI, this technique is a parallel communication where several
bits are sent as a whole, on a link with several parallel channels. This is
contrast to serial communication where data sent one bit at a time. SCSI could transmit
data as 160Mbps within maximum distance 25m, but it consider as an old
technique, because it allows to be connected with limited number of servers.
2- Fiber channel, this
technique is high speed technology used to connect computer data storage, as
well it consider as very speed connection type for storage area network. So fiber optic cables is used to connect data
storage units with servers where 10Gbps is the maximum rate of data
transmission, due to that high rate of data transmission with fiber optic, it recommended
if we have live stream conference and we want to video record at the time
sending the recorded video to the storage units.
3-Disk array is data storage system that contains multiple disk storage, cache memory and
controller.
There is some of the disk storage leave empty
so that, if one of the storage unit becomes full, the controller efficiently
distributes the coming data across the empty storage while cache faster the
process of data storage.
Topologies
of SAN,
There are physical topology and logical topology for the
environment of fiber channel.
The logical topology is the path established between the
operation system with devices “switch or hub” and the associated storage ports.
The physical topology is, interconnects among devices “storage
units, switches, servers…”
The figure below describes with more details:
1- Point to point
topology,
consider as the simple design, in short it’s a server connects with
disk storage, means no need for a fiber layer. Within this topology many servers can
connect with the storage unites depends on the storage unit ports.
2- Arbitrated loop
topology,
This type of topology has fiber
layer, where fiber channel hub used to connect between the servers and storage
unit. But as the Hub is not efficient and old to be used switch is the
replaced.
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