Serial ATA is making massive strides in the majority of storage market and has become the clear disk interface of choice where capacity and price is a higher priority than performance. It pops up in a wide range of SMB and mid-range storage applications such as NAS, DAS and iSCSI or simply as general storage for entry-level and departmental servers. Along with Adaptec, AMCC has traditionally offered an extensive range of SATA RAID controllers and the 3Ware 9550SX-8LP delivers an impressive range of features and as our performance tests reveal a fair turn of speed as well.
The card delivers eight SATA ports and supports both 3Gb/sec speeds and NCQ (native command queuing). The latter specification aims to improve performance for random I/O operations by taking multiple requests for disk operations and reordering them so they are executed more effectively. For normal operations the drive heads have to deal with requests in the order they are received which will result in inefficient operations. Port multiplier technology is also supported by the 9550SX which allows multiple drives to be attached to a single port. A useful application for this would be for servers or storage arrays kitted out with the appropriate multipliers on their drive backplanes as more drives can be connected to the controller and cable related clutter reduced as well.
The 9550SX will fit well it with a range of servers and appliances as it is only a half-height card. All the SATA ports are located on the upper surface and presented as five connector blocks each with an upper and lower port. However, even though there are ten ports the two lower ports on the blocks set further back on the card are not active. The 9550SX is equipped with a 200MHz PowerPC processor and employs a Marvell 8061 8-port SATA controller chip. It comes with a reasonable compliment of cache memory as it has 128MB of PC-3200 memory although this is embedded on the card and there are no options to upgrade. However, a battery backup pack for cache protection in the event of a power failure is available as an option and costs less than £100.
Installation is easy enough and the card and attached drives can, if you wish, be configured from a simple BIOS screen which allows you to create, delete, modify or rebuild arrays and add a hot-standby drive to an existing array. There are plenty of array options to choose from as the 9550SX supports RAID-0, -1, -10, -5 and -50. Youll need to look to Adaptec and Promise Technology if you want the latest SATA RAID-6 and -60 arrays and their dual-drive redundancy. The 9550SX doesnt support these and wont be in the future either as AMCC has no plans to implement this in the cards firmware. JBODs arent supported either and individual drives will not simply appear to the OS as available drives. These now need to be configured as single disk units and the reason for this is it allows them to take advantage of features such as caching.
For general management and monitoring AMCC provides its 3DM2 utility which allows the controller to be accessed locally and remotely via secure HTTPS sessions Adaptecs Storage Manager utility doesnt currently support SSL encryption. The utility offers two levels of access where a User can view all pages within the 3DM interface but not change anything whilst an Administrator can take full control. The main interface is easy enough to get to grips with and opens with a basic summary of the card along with alerts for warning or error messages.
The Information tab offers more detail and provides a complete rundown of the controller, RAID arrays and individual drives and the arrays they belong to. From the Maintenance tab you can select array rebuild and verification priorities and opt for automatic rebuilds when replacing failed drives. Rebuilds can hit system performance harder than running on a degraded array but AMCC has this covered as a scheduler allows you to run these tasks out of normal hours on selected days of the week. Alerting facilities are good as the controller can send emails to multiple recipients when problems are detected.
For performance testing we called in a Supermicro dual 2.4GHz Xeon system with 2GB of PC2100 memory and running Windows Server 2003. Using Western Digital 3Gbps WD2500 hard disks we ran the open source Iometer configured with four workers, a 256KB transfer request size and 100 per cent sequential read operations. With a single drive we saw a very reasonable 53MB/sec - the same as the servers own Ultra320 SCSI disk. With two WD drives in a RAID-0 stripe speed increased to an impressive 245MB/sec which leapt to 488MB/sec with a four drive stripe. Speed ramped up massively for an eight drive stripe with Iometer reporting a whopping 720MB/sec read rate. RAID-5 performance was also good with a four drive array returning no less than 514MB/sec read rates.
The 9550SX-8LP offers a very good range of RAID-related features that compares well with the competition. Pricewise, it looks good value, management and monitoring tools are extensive and its excellent performance cannot be ignored.
The 9550SX-8LP certainly delivers on performance making it a good choice for a wide range of storage applications in rack and pedestal chassis. If you want dual-drive redundant arrays then look elsewhere but otherwise AMCC is offering a good value SATA RAID package