Storage Servers vs. Disk Arrays
There is sometimes a misunderstanding between storage servers and disk arrays. Exactly where does one end and the other begin?
A storage server can have as many as 24 disks — enough to quality as an array. Disk arrays, however, can have hundreds of disks. So where do you draw the line?
A storage server is usually stand-alone and not connected to other servers. Multiple servers, however, typically connect to a disk array. Disk arrays, too, often connect to a server that could be styled a storage server.
The storage server is the intelligence that goes in front of the array. In this arrangement, the server can manage several tiers of storage. It can even arrange the replication of data from one tier to another.
A storage server serves the storage, and the disk array is the storage and typically speaks to files and talks to people or applications over Ethernet, whereas a disk array is a low-level block device that speaks only to an operating system.