| In an article titled "No Waiting: Considering the | | | | |
| Benefits of Solid State Disks,"1 authors Ramon | | | | In this study we have selected 15,000rpm drives, the |
| Sandoval and Maneesha Lee highlighted the growing | | | | fastest available rotational hard drives in the market |
| popularity of solid state disks (SSDs) as accelerators | | | | today. Both drives feature Fibre Channel interfaces |
| for enterprise databases. The authors cited the rapid | | | | and are enclosed in the same 3.5-inch form factor. |
| expansion of the SSD industry as a result of relational | | | | Since this analysis will focus more on cost versus |
| database applications, with SSDs being deployed as | | | | IOPS performance alone, disk capacity is totally |
| storage devices for hot files2. In particular, Sandoval | | | | irrelevant in this analysis. |
| and Lee revealed that a major portion of enterprise | | | | To cancel out the advantages (and disadvantages) |
| SSDs are installed in high-end database applications | | | | brought by JBOD modules from different |
| running Sybase, Oracle and Informix, along with SAP | | | | manufacturers, this analysis will utilize a generic JBOD |
| running on top of these databases. | | | | module that has the same form factor (2U) and disk |
| Aside from this write-up, several reports and white | | | | capacity (12 3.5" disks) as the E-Disk(R)SAN S2F-J |
| papers emphasizing the performance benefits of | | | | from BiTMICRO. |
| SSDs have already been published, and hard disk | | | | |
| drive makers such as Samsung have expressed | | | | Disk/Module Performance |
| interest in this storage line. The only remaining | | | | There has been a dearth of storage hardware |
| question is, are SSDs a viable alternative for | | | | literature that tackles HDD performance as measured |
| price-conscious buyers who are running | | | | in I/Os per second, as most drive manufacturers |
| performance-hungry OLTP apps? | | | | publicize disk performance in terms of MB per second |
| The objective of this article is to examine the | | | | (MBps). However, IOPS statistics are critical in random |
| benefits of utilizing flash SSD-enabled storage system | | | | access applications such as OLTP and data |
| as cache storage in an enterprise environment. A | | | | warehousing, and storage subsystem suppliers post |
| comparison will be made between conventional | | | | mission-critical IOPS data in their website. Similarly, |
| storage systems (featuring HDDs) and solid-state | | | | BiTMICRO Networks conducted benchmark tests in |
| disk-based network storage in terms of performance | | | | November 2003 for its E-Disk(R)SAN featuring |
| and overallcost per IOPS. | | | | twelve E-Disk Fibre Channel channels. IOPS results for |
| Market Trends | | | | a small-block (4KB), sustained random read workloads |
| Storage users are buying more midrange and lower | | | | are posted in the succeeding table. |
| cost systems, according to International Data Corp.'s | | | | |
| (IDC) quarterly worldwide disk storage systems | | | | To compute for the generic JBOD's performance |
| report released December 2004. Revenues grew 3.5 | | | | rating, we multiplied the 15,000RPM HDD's maximum |
| percent year-over-year to $3.4 billion in the third | | | | IOPS rating of 435 with the maximum number of |
| quarter of 2004. Although revenue growth was | | | | disks in the enclosure (12). The result, 5,220, is the |
| smaller compared to previous quarters, IDC noted | | | | theoretical maximum IOPS for small block (4KB) |
| rapid growth in storage capacity, rising 50.5 percent | | | | random reads. |
| year over year to 310 petabytes. It is the largest | | | | Table 3 figures already show a wide disparity in I/O |
| growth rate posted over the last seven quarters, the | | | | ratings (more than 1100%) both at the drive and at |
| report said. | | | | the enclosure levels. To achieve the desired |
| IDC analyst Brad Nisbet says the results confirm the | | | | performance of 100,000 IOPS, we simply add more |
| slow but steady growth of midrange and lower | | | | enclosures and drives in the JBOD setup accordingly |
| segments, like ATA-based storage. "We saw an | | | | (Table 4). |
| increase in the growth of petabytes shipped, which is | | | | |
| yielding the largest dollar per gigabyte pricing decline in | | | | To compute for the dollar cost per IOPS, we add up |
| seven quarters and points to a growing share of | | | | the equipment cost and divide the amount by the |
| higher-capacity, lower-cost disk drive deployments | | | | total IOPS generated. Equipment includes the drives, |
| and a broader variety of products offered by the | | | | enclosures, switches and cabinet. However, for the |
| major vendors," he explains. | | | | purpose of this analysis, it is assumed that each |
| Another contributing factor to the growth of | | | | setup will utilize one switch. Therefore the cost of |
| networked storage, in particular midrange systems, is | | | | switches may not be included in the computation |
| the stiff price competition among sellers in their bid | | | | since they would just cancel each other out. List |
| to corner a slice of shrinking IT budgets. Price | | | | prices for the generic JBOD setup are based on web |
| consciousness is also echoed in the way enterprises | | | | prices as of June 29, 2005. |
| handle their storage requirements. Consolidation is | | | | |
| now a must as it increases storage manageability, | | | | Analysis of Results |
| maximizes capacity utilization, and lowers overall TCO. | | | | To compute for the $ cost per IOPS, the following |
| However, this strategy puts a strain on server | | | | formula will be used using figures from Tables 4 and |
| performance, especially for I/O intensive applications | | | | 5. |
| such as: | | | | Total IOPS / Total Cost = $ per IOPS |
| - Aerospace, telemetry and data acquisition | | | | Table 6 figures reveal a significant difference in |
| - Data backup and recovery as well as migration | | | | investment costs when building a storage system for |
| - Energy exploration and geosciences | | | | database/OLTP applications using a generic JBOD |
| - Medical sciences, including healthcare and imaging | | | | versus an E-Disk(R)SAN. On a $/IOPS level, the |
| - Online transaction processing (OLTP) | | | | rotational HDD-based JBOD array costs 303.8 percent |
| - Paging, log, journal and index files | | | | higher than the E-Disk(R)SAN, thanks to the |
| - Still and moving video surveillance | | | | significantly higher I/O rating of the S2F-J solid state |
| - Video editing and processing, including | | | | disk subsystem which resulted in a lower number of |
| post-production | | | | drives required. Another factor that drove down |
| - Video on demand and video services | | | | equipment cost is the smaller cabinet space |
| - Weather forecasting and simulation | | | | requirement of the S2F-J (24U) as opposed to the |
| OLTP is a critical segment in enterprise storage as | | | | generic JBOD (48U). In fact, the SSD-based |
| most banking, trading and supply chain transactions | | | | subsystem can be easily integrated into existing data |
| are now transferred online, with users demanding | | | | centers since it is composed of only two 2U modules |
| faster and more responsive systems. In selecting the | | | | as compared to the 20 modules required for the |
| most cost-effective, high-performance storage | | | | HDD-JBOD setup. Removing the 24U cabinet (costing |
| device for this application, IT and data center | | | | $4,298) in the S2F-J setup would drive down $/IOPS |
| administrators have HDDs and SSDs as options. The | | | | even further. |
| wide variety of available models in the market and | | | | Conclusion |
| lower price per unit makes the HDD as the most | | | | Enterprises are looking for ways to generate more |
| logical solution for enterprises, providing the best | | | | IOPS in the same data center space, as well as |
| return on investment. Or does it? | | | | cost-effective means of scaling their storage |
| Cost Analysis | | | | performance requirements. The examples in the |
| Let us examine a setup involving a generic SAN | | | | preceding section prove that solid state flash disks |
| attached JBOD setup comprised entirely of | | | | are cost effective solutions for performance hungry |
| 15,000RPM rotational HDDs as opposed to a | | | | applications, not only in terms of $/IOPS in general, |
| BiTMICRO E-Disk(R)SAN S2F-J featuring flash-based | | | | but also for deferring costly server upgrades in I/O |
| E-Disk SSDs. The objective of this analysis is to | | | | bound applications. This article focuses mainly on the |
| compare the capital investment needed to acquire a | | | | cost advantages of the SSD subsystem in an |
| networked storage solution that can offer peak | | | | equipment level. The gap between SSDs and HDDs |
| performance of 100,000 IOPS in a typical OLTP | | | | widens further when other factors such as power |
| database I/O application. | | | | consumption of 220 rotational hard drives versus 21 |
| Hardware Specifications | | | | solid-state flash disks, storage space (and the burden |
| The tables below detail the technical specifications of | | | | that these subsystems will impose on the data |
| the drives and JBOD modules used in our | | | | center's cooling system), and better reliability (MTBF) |
| comparative analysis. | | | | are taken into consideration. |