The solid state hard disk has always been held to ransom by memory prices but as these decrease we’re starting to see more products emerging that are based on this technology. The latest RamSan-320 from Texas Memory Systems (TMS) is firmly aimed at the enterprise sector and offers up to 64GB of storage implemented in fast SDRAM memory combined with top quality fault tolerance. It’s suited to wide range of operational scenarios as it supports up to eight 2Gbps fibre channel links and can slot easily into a SAN (storage areas network) or be connected directly to servers where, in both cases, it appears simply as a very fast hard disk resource. The uses it can be put to are endless with TMS touting it as an ideal storage solution for applications such as web services, databases, video on demand and data warehousing.
Underneath the sturdy lid you’ll find a tidy interior with the custom system board looking after the memory cards and up to four dual-port 2Gbps fibre channel HBAs (host bus adapters) which can be configured to provide multiple redundant network paths. To one side is a management card which offers a serial port connection and web browser access. Power is handled by a pair of dual redundant supplies. Power fault tolerance gets even better as three separate UPSs are located at the front and aim to provide up to twenty-five minutes of emergency power.
The volatility of SDRAM means backup is essential in the event of a power failure and the triplet of hard disks offer three scenarios. The unit comes as standard with a mirror mode which sends all write operations to memory to the disks as well, to provide a real-time backup. This will have a minor impact on performance which can be avoided with the Data Sync mode that only allows read and write operations to go to the memory. In the event of a power failure, or a normal shutdown, the backup UPS supplies comes into operation. All data resident in memory is written directly to the hard disks, allowing the system to be safely powered down without data loss. The optional Active Backup offered by TMS takes the middle ground as it attempts to back up as much data from memory to disk as possible without impacting on general performance. As only a comparatively small amount of data will need to be written to the disks to complete the backup the system can be shutdown much quicker. Installation is a swift affair as you can manually assign an IP address to the unit using the control panel at the front, or a local serial connection and CLI (command line interface) session and then move over to the tidy web browser front end. This provides a simple graphic of the RamSan-320 with hot-spots for easy access to each component.
For testing we used a QLogic
SanBox2-8 eight-port 2Gbps fibre channel switch and linked up a pair of Windows 2000 Server systems using 2Gbps QLogic SANBlade QLA2310F HBAs. Initially we connected the RamSan-320 with all 16GB configured as a single LUN (logical unit number) and ran separate instances of the open-source Iometer utility using 64Kbyte transfer requests and ten outstanding I/Os per client. This reported rates of 98Mbytes/sec and 110Mbytes/sec respectively which equated to a cumulative total of 1,664Mbits/sec – close to wire-speed for the single 2Gbps fibre channel connection linking the RamSan-320 to the switch. Next we created three separate LUNs, assigned them to different network ports and direct-attached three clients. Re-running Iometer on each system saw transfer rates of 191, 195, and 196Mbytes/sec respectively for a stunning cumulative total of no less than 4,656Mbits/sec. The RamSan-320 provides dedicated paths to memory for each fibre channel port so adding more clients would have ramped these speeds by approximately 195Mbytes/sec for each instance.
Overall, the RamSan-320 looks a superb choice for enterprises that have a large and impatient user base that can’t be kept waiting. Total capacity does look a bit tame when you consider that the latest Serial ATA hard disks can deliver up to 250GB but you simply won’t find this level of performance being offered anywhere by conventional disk-based storage solutions.
The ideal storage solution will always be one that involves the least moving parts and the solid state disk is the natural successor to high-speed spindles and platters. The RamSan-320 provides a comparatively small amount of storage for the price but enterprises that need fast access to data will need to consider this solution as nothing else touches this technology for performance.