Rackable iSCSI system stacks up

Meeting growing storage requirements is no longer just a matter of accommodating a few more files. Thanks to legislation that mandates the archiving of e-mail and customer records and to the increased use of multimedia and VoIP apps, storage needs can double or triple in a very short time. 

Free IT resource TechNet: More ways to know it, share it, and keep it running. Sponsored by Microsoft Free IT resource Attend the SOA Executive Forum: Breaking SOA Bottlenecks SOAExecForum.com/may2007 Sponsored by InfoWorld Rackable Systems S3118-iSCSI Rackable Systems, rackable.com Very Good  8.3 criteria score weight Management 7 20% Performance 8 20% Reliability 8 20% Scalability 9 20% Interoperability 9 10% Value 10 10% Cost: As tested (4TB), $14,750; with 400GB SATA drives (7.2TB), $19,750; also available as storage server with Windows or Linux installed Platforms: Any host that supports iSCSI Bottom Line: Rackable’s S3118-iSCSI appliance combines a basic iSCSI feature set and good performance. The bundled Wasabi Storage Builder software makes configuration a breeze, and the potential for using the box as a Windows or Linux storage server offers additional appeal. Shops looking for easy and flexible storage expansion will be hard-pressed to find a better value. About our Reviews and Scoring Methodology

Although FC (Fibre Channel)-based SAN technologies offer easy-to-scale, high-performance solutions, there's also a place in enterprises for less-expensive, high-capacity systems. To that end, iSCSI SANs offer an easy, flexible, low-cost way to add storage for servers in situations where maximum throughput is not required.

Rackable Systems is best known for its blade server systems and Linux-based clusters, but its iSCSI appliances also show a good grasp of what the market wants. The S3118-iSCSI appliance system I received for review was a no-frills 3U storage system that holds as many as 18 250GB or 400GB SATA RAID Edition drives. The S3118 doesn't include storage management software, but the configuration software is excellent, performance is good, and the price is hard to beat.

Nuts and bolts

The Western Digital RAID Edition drives are engineered to run continuously -- rather than intermittently, as workstation drives are designed -- and are rated at a million hours MTBF (mean time between failures). The RAID Edition drives counter the objection some administrators have about SATA drives, namely that they are not as reliable as SCSI or FC drives. Only time will tell, but the RAID Edition drives should be reliable enough for most server applications.

In addition to slots for 16 drives in front, the S3118 has two additional drive slots in back, as well as an Ethernet management port, two Gigabit Ethernet network ports, and the standard assortment of server ports. The S3118 can function as a dumb iSCSI target or be configured as a Windows or Linux server using the two rear drives as mirrored boot drives. This requires installing the OS and then configuring the storage system to work with it, but it gives you a full server for the same cost as the basic appliance. A NAS version of the same hardware is also available.

The system I received had 18 250GB RAID Edition hard drives, an AMD Opteron 248 processor, 4GB RAM, two 3ware RAID controllers, two Gigabit Ethernet ports, and the management processor with a separate out-of-band Ethernet management port. Along with the dual controllers, redundancy features include dual power supplies and dual Ethernet interfaces. Naturally, multiple boxes can be clustered as well.

As an iSCSI appliance, the system is very easy to set up. It is configured with a default IP address on its embedded management interface, so a serial terminal or KVM connection is not necessary to make the initial configuration, just a Web browser. After the initial network configuration has been completed, the rest of the configuration is handled through the Wasabi Storage Builder 1500i for iSCSI Appliances software that Rackable uses for iSCSI services. The system comes with a default configuration, but changing the RAID configuration or volumes is simple and straightforward. In addition to software iSCSI clients, the S3118 supports Intel and Alacritech iSCSI accelerators.

If you've ever built an IP SAN, you know that configuring iSCSI can sometimes be problematic. Getting the necessary iSCSI credential, portal, and node settings, permissions for servers, and security settings to work on both ends isn't always easy or well documented. I found the Wasabi software did an excellent job, however -- everything worked the first time, both with Windows and Linux servers. The documentation is clear and concise, leading even an inexperienced user through the necessary steps to add storage to either a Windows or Linux server.

An iSCSI portal functions as the network that accesses the system. Wasabi offers excellent control over the configuration while providing a basic setup that will suffice for most users. The node settings determine the amount of disk space to be made available to a particular server. After you have set these, however, they can't be changed -- you can't expand the size of a node attached to a server dynamically. Wasabi supports iSNS (Internet Storage Name Service), an auto-discovery protocol for iSCSI, and it worked well.

What it is

You don't get many bells and whistles in the Wasabi software. You can create disk sets and volumes, set the RAID level to 1, 5, or 10, and make the volumes available to your servers. Volume spanning is supported, so if you want to make all 16 drives into one large volume, it can be done. But additional functions such as replication, virtualization, or dynamic expansion of volumes would require additional, third-party software.

What the S3118 does, it does well. It sustained server connections on two separate Gigabit Ethernet ports with transfer rates of 91MBps, which is about as good as you're going to get from iSCSI over Gigabit Ethernet.

The S3118-iSCSI is a basic iSCSI system that provides good performance, ease-of-use, and great value. The flexibility of converting the appliance to a server simply by installing an OS makes this system even more attractive. If you're looking for sophisticated storage management features, you won't get them here, but at less than $20,000 for a 7TB system, you shouldn't expect extras. Rackable Systems should be on the short list for anyone looking for a simple way to add storage to existing servers.