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