Six iSCSI SANs unleashed
Adaptec, Celeros, EqualLogic, Intransa, NetApp, and Rasilient move our megabytesFollow @pvenezia
Because the 4KB tests are relative indicators of many real applications, such as Microsoft Exchange, I've included those results here; the results of tests for 8KB, 32KB, and 256KB block sizes are included in the online version of this article. The accompanying charts show the numbers gathered from Iometer tests on Red Hat Enterprise Linux 4 with the linux-iscsi software initiator. Given the sector offset issues that cropped up during Windows testing, the Linux results are the best baseline numbers available for all units.
Adaptec Snap Server 18000
Adaptec's Snap Server 18000 will appeal to the lower-budget storage buyer who wants NAS-plus-SAN functionality without the costs or complexity of a Network Appliance filer. In fact, the Snap Server speaks even more network file-sharing protocols than the NetApp unit, supporting Apple file sharing via FTP and AFP (Apple File Protocol) as well as NFS and CIFS shares.
The Snap Server 18000 is built on Linux, with a standard mainboard and PC connections at the back of the unit. The system cannot be configured via KVM, however, but will request DHCP on first boot. Additional configuring is performed via the Web GUI. The LCD panel on the front helpfully shows the IP address assigned to the primary NIC to assist in initial configuration.
The Web GUI is very lean -- the most Spartan of all the arrays in the test -- and functional but gives the impression that iSCSI support was rather hastily added to the appliance. For example, although you get support for iSNS (Internet Storage Name Service) servers and CHAP (Challenge Handshake Authentication Protocol) authentication, there is no way to restrict iSCSI volumes to specific hosts via IQN (iSCSI Qualified Name).
Internally, the Snap Server 18000 sports dual 3GHz CPUs and 2GB of RAM. The storage is limited to eight internal disks, but additional disk arrays can be connected via FC to expand the capacity of the appliance. The SATA drives are driven by an internal SATA controller that does not support hardware RAID. Instead, RAID is supplied by Linux software RAID, which is quite capable but requires significant processing resources, which explains why this appliance has dual CPUs.
Similar to the Celeros EzSAN, the Snap Server 18000 neither provides redundant features nor can be clustered with another appliance to provide fail-over. Snapshots are limited to read-only. On the plus side, you can expand the array by adding a disk shelf via FC.
The Snap Server is the Fiat to the NetApp's Ferrari. It's definitely suitable for use in smaller shops looking to provide CIFS or NFS services to a network -- and possibly even as storage for Exchange or in disk-to-disk-to-tape backup scenarios -- but its usefulness as a resilient iSCSI target is limited. Nevertheless, the nice price makes this SAN a good fit for smaller budgets that need big storage.
Celeros EzSAN XR23
The EzSAN XR23 is a 2U appliance that appears to be a regular server chassis with 12 SATA drives in hot-swap cages in the front, mounted behind a black bezel. On the back, you'll find a standard mainboard connector panel with keyboard, mouse, and USB ports, as well as two copper Gigabit Ethernet ports. Thus, the EzSAN is really a standard server with an embedded NetBSD OS, 12 drives, and a 3Ware 9500S-12 SATA RAID controller. Of course, that's one of the reasons it's the lowest-cost array in the test.