What are the benefits of SANs?

[KCS_1]

I am very confusing what are four benefits of SANs?

a. Increased Productivity
b. Increased Performance
c. Increaesd Disk utilization
d. Centralized management
e. Availablity with multiple data paths
f. Secutiry with multiple paths


It was a question of a sales license of HP that I choosed incorrect answer and make sure what those are.



Thanks.

[Luk Vandenbussche · Accepted solution]

I would say

B
C
D
E

[Sheldon Smith]

Definitely increased disk utilization compared to direct attached storage. And centralized management is typically a function of having a SAN. As far as performance goes, certainly any current HBAs I've seen are significantly faster than direct connected drives. Plus, you typically have multiple paths. This means faster IO, including faster boot times. Whether or not that also translates to increased productivity is more a function of if your operation can make use of the faster IO.
I work with EVAs quite a bit, and since they have multiple IO ports, they are normally connected to a pair of (unconnected) switches running in parallel. So typically each host has a pair of HBAs connected to those switches. This provides the above mentioned multiple data paths, however, either the OS needs to be natively aware of how to handle multiple paths, or the system will require a multipathing layer to properly handle the existence of the multiple paths. For example, MS Windows would need MPIO installed on each host. Lastly, while the switches should be zoned such that each host can access the storage, but the hosts are isolated from each other (the SCSI protocol was designed for a *single* host), security (LUN protection) is more the function of the storage system itself.
Hope this helps.

[Adam Garsha]

One thing that I would recommend is multiple "medium" sized arrays vs. one-big all-in-one-basket array. (If that is a choice that you are facing.) Otherwise, you will face "g: increased risk of catestrophic whole-enterprise-is-down disaster". In short, you should have at least 2 arrays with some planning for data redundancy. Then, a-d are all true, usually. I'd add, "h: increased flexibility"

[KCS_1]

Thanks for all.