The 800 Series appliances are among the largest network-attached storage devices available. Auspex's 4Front NetServer 2000 has a capacity of 9 terabytes and EMC's Celerra a capacity of 28 terabytes. Dave Durkee, chief information officer for application service provider NetLedger in San Mateo, Calif., says that while size is important, his company's applications are running out of bandwidth first. In the clustered 840C configuration, both servers can failover for the other and continue operations unabated. That's not good enough.
SANs require additional hardware interfaces in each machine. . . .
NAS only needs the network adapter. The 840 also has redundant, hot-pluggable power supplies, fans and disks for increased fault tolerance. It can be configured as a RAID 4 device, in which only read operations overlap, or in a configuration where data is replicated from one 840 to another. Snapshot back-up capability is also possible, as well as data mirroring. Both are available now.