| Blade server computing is fast transforming | | | | these add-ons. |
| the server industry with a host of advantages | | | | |
| in terms of design, functionality and total | | | | Rugged Capabilities |
| cost of ownership. By separating CPU and | | | | |
| memory from other components such as cabling, | | | | Most blade server vendors are searching for |
| power supply, network connectivity and | | | | more efficient means of cooling densely |
| cooling systems, blade servers significantly | | | | packed blades. Hewlett Packard's "dynamic |
| reduce massive enterprise server | | | | smart cooling" initiative seeks to control |
| architectures into highly compact and dense | | | | heat by focusing cooling on areas identified |
| form factor. According to market research | | | | as "hot spots." For its part, IBM is working |
| company IDC, the blade server market is | | | | on liquid-cooled heat sinks for server |
| projected to represent nearly 29 percent of | | | | processors and water-cooled cabinets. |
| server unit shipments worldwide by the end of | | | | However, these ideas are still under |
| 2008. | | | | development and are not available now. |
| | | | |
| Although its inherent compact design enhances | | | | Unlike an HDD, a flash SSD generates minimal |
| scalability and ease of use for IT | | | | heat since it has no moving parts, and users |
| administrators, a blade server poses design | | | | can expect the same degree of high-level |
| challenges with regard to the installation of | | | | performance in a wider operating temperature |
| direct attached storage (DAS) devices. Since | | | | range. These rugged features make flash SSD |
| several blades already share the same power | | | | the most suitable storage platform for Level |
| supply, cooling system and chassis, the most | | | | 3 NEBS-compliant servers. NEBS (Network |
| logical thing to do is to utilize a | | | | Equipment Building System) refer to a set of |
| low-power, low-heat and compact hard disk | | | | standards established by Bellcore (now known |
| drive. The first thing that comes into one's | | | | as Telcordia) to determine electromagnetic |
| mind is the 2.5-inch mechanical disk drive, | | | | compatibility, thermal robustness, fire |
| the same disk drives installed in notebook | | | | resistance, earthquake and office vibration |
| computers. However, for enterprise-wide | | | | resistance, and transportation/handling |
| applications, a better solution exists in the | | | | durability of telecom equipment. Telecom |
| form of solid-state disks (SSDs), in | | | | carriers deploy equipment to remote locations |
| particular flash SSDs. | | | | with unpredictable operating conditions, and |
| | | | NEBS allows them to identify equipment that |
| Flash SSDs are high-performance, rugged | | | | can provide a high degree of reliability and |
| plug-and-play storage devices that contain no | | | | safety to their network. |
| moving parts. Using flash memory chips for | | | | |
| storage, these devices are available in the | | | | The E-Disk Advantage |
| same industry-standard form factors | | | | |
| (2.5-inch, 3.5-inch and PMC) and interfaces | | | | BiTMICRO Networks, a leading player in the |
| (Fibre Channel, SCSI, ATA/IDE) as hard disk | | | | flash SSD arena, successfully penetrated the |
| drives, but instead use flash memory chips in | | | | military/industrial markets with its |
| lieu of rotational magnetic disks to store | | | | ruggedized E-Disk flash SSDs. These models |
| data. This article seeks to explain and | | | | are guaranteed to operate in extreme |
| illustrate how flash SSDs stack up against | | | | temperatures, from -60°C to +95°C. |
| other storage devices in blade server | | | | Other environmental specs are likewise |
| applications. | | | | impressive, up to 150Gs of operating |
| | | | vibration and up to 1,000Gs of operating |
| Flash SSDs vs. DRAM SSDs | | | | shock, making enterprise and carrier class |
| | | | applications a breeze. |
| One SSD variant in the market today is the | | | | |
| DRAM SSD. Used mostly in large, rackmount | | | | One variant is the E-Disk PCI Mezzanine Card |
| architectures, this device cannot be | | | | (PMC)-based plug-in flash SSD module. |
| considered a viable alternative in blade | | | | Suitable for blade servers (with PMC slot) |
| server storage due to several design | | | | that require a reliable, direct attached |
| limitations. Owing to the volatile nature of | | | | storage device, it features horizontal |
| DRAM memory, a DRAM SSD requires its own | | | | connectors that allow parallel fit onto a |
| power supply, cooling fan and disk backup for | | | | blade, giving plug-and-play advantages to |
| data retention. These components eat up | | | | system administrators. The E-Disk(R) PMC can |
| valuable space inside the drive chassis, | | | | also be used as a boot and/or storage device |
| limiting total storage capacity (less room | | | | for carrier boards such as CompactPCI, VME |
| for memory chips) and form factor (smallest | | | | and MultiBus, and almost any other type of |
| DRAM SSD is 3.5-inch). Consider further its | | | | single board computer. |
| weight, and you'll have a recipe for disaster | | | | |
| in embedded systems design. | | | | In the enterprise arena, the rising |
| | | | deployment of business intelligence, OLTP |
| Flash SSDs vs. HDDs | | | | (online transaction processing), decision |
| | | | support systems and other |
| As mentioned earlier, the most important | | | | transaction-intensive applications place a |
| factor in finding the right DAS for blade | | | | premium on rapid information transfer, access |
| servers is its impact on overall system | | | | and retrieval. Fibre Channel and Ultra Wide |
| performance and cost effectiveness. In terms | | | | SCSI E-Disk solid-state drives' impressive |
| of power consumption, mechanical hard disks | | | | performance up to 70 MB/s sustained reads, 48 |
| typically devour around 500mA while flash | | | | MB/s sustained writes and 12,500 IOPS make |
| SSDs consume a mere 50mA. The difference may | | | | them ideal for applications that exhibit |
| seem insignificant in small enterprise apps, | | | | grueling, rapid-fire data access brought |
| but for huge data farms, the cost savings | | | | forth in transactional and high storage |
| become apparent. This further enhances the | | | | bandwidth environments. |
| blade server's advantage over proprietary | | | | |
| systems with regard to operational costs. | | | | Conclusion |
| | | | |
| The reliable performance of mechanical disk | | | | At present, blade servers utilize DAS mainly |
| drives can only be ensured if these drives | | | | for system boot and application storage, with |
| operate within specified temperature ranges. | | | | a Fibre Channel interface designed into the |
| As drive manufacturers introduce newer models | | | | server to allow for a separate SAN |
| featuring spindle speeds as high as 15,000 | | | | connection. Flash SSDs can help improve, not |
| RPM, cooling has emerged as a major issue. In | | | | impede, system performance with faster access |
| fact, some suppliers are providing a | | | | times, high I/O rates and solid-state |
| dedicated cooling fan or fan/heatsink combos | | | | durability. Consider other factors such as |
| for optimum high-speed drive performance. | | | | hot swappability and ease of deployment, |
| Unfortunately, the cooling systems of blade | | | | flash SSD is certainly an ideal DAS solution |
| servers are shared, and there's no room for | | | | for blade servers. |