1. 2730/2730T/5730 Performance Comparison 20 May 2008

2. Dot Hill Systems Confidential / Covered under NDA NDA Notification This presentation contains information related to projects that are currently in planning and/or development stages. This information represents the current intentions of Dot Hill Systems. However, all aspects of these projects, including, but not limited to funding, availability, shipping dates, configurations, capacities, performance, and all other characteristics are subject to change and/or cancellation without notice. This material is confidential to Dot Hill Systems and should be disclosed to external entities only under the terms of an executed non-disclosure agreement (NDA). Distribution of this material to Dot Hill Systems Field Representatives should be done through the Dot Hill Systems NDA process. The information contained herein is considered privileged, confidential and protected from disclosure. If you are not the intended recipient or their employee/agent responsible for its delivery, you are requested to refrain from any duplication or distribution of this message or its contents, in respect of the rights of the designated recipient and sender, and to delete it from your computer. 2

3. Dot Hill Systems Confidential / Covered under NDA About This Presentation Project Name “Neptune” refers to the 2730/2730T Project Name “Krypton” refers to the 5730 The performance information contained in this presentation was obtained within the Engineering Verification Lab using IOMeter Actual performance results within specific application use may vary from the contents of this presentation This information is provided only as a reference point and no “performance tuning” has been applied 3

4. Dot Hill Systems Confidential / Covered under NDA 2730 vs. 5730 Quick Reference 4 Sequential Access2730/2730T5730Comments Read Disk Bandwidth (RAID5) Fail-Over: 550 MB/s Active/Active: 1100 MB/s Fail-Over: 790 MB/s Active/Active: 1580 MB/s 5730 44% faster read throughput PCIX/DDR dependent CPU independent Write Disk Bandwidth (RAID5) Fail-Over: 340/380 MB/s Active/Active: 640/730 MB/s Fail-Over: 575 MB/s Active/Active: 980 MB/s 5730 34% faster write throughput PCIX/DDR dependent primarily CPU dependent on lower end Read Disk IOpsActive/Active: 29K/48K IOPs Active/Active: 112K/160K IOPs 5730 330% faster read transactions PCIX/DDR independent CPU dependent Read Cache Hit Same Sector Active/Active: 100K/150K IOPs Active/Active: 320K/375K IOPs Same sector transaction rate shows the power of 5730 FC target and CPU low latency performance Write Disk IOps (RAID5) Active/Active: 11K/19K IOPs Active/Active: 33K/41K IOPs 5730 215% faster write transactions PCIX/DDR independent CPU dependent

5. Dot Hill Systems Confidential / Covered under NDA 5730 (5730) Performance Quick Reference 5 Sequential Bandwidth Performance Controller Configuration Host Access VDisk Type MeasurementReference / Comments Dual (Active/Active) ReadAll1580MB/sFour hosts systems connected, each accessing one LUN, two LUNs owned per controller. Note: RAID10 requires additional total drives to meet maximum number. Dual (Active/Active) WriteRAID0 RAID5 RAID6 RAID10 RAID50 1271 MB/s 987 MB/s 914 MB/s 882 MB/s 1003 MB/s Sequential Transaction Performance Controller Configuration Host Access VDisk TypeMeasurementComments / Reference Dual (Active/Active)ReadRAID5143.1K IO/s 160K IO/s Four hosts systems connected, each accessing one LUN, two LUNs owned per controller. Single (Fail-Over) Dual (Active/Active) WriteRAID539.4K IO/s 25.5K IO/s Dual (Active/Active)Same Sector N/A375K IO/s512B read same sector (cache hit) access using four hosts systems connected, each accessing one LUN, two LUNs owned per controller. Random Transaction Performance Controller Configuration Host Access VDisk Type Measurement Dual (Active/Active)ReadAll24.9K IO/s Single (Fail-Over) Dual (Active/Active) WriteRAID5 RAID6 RAID0 RAID10 5.4K IO/s 4.1K IO/s 3.1K IO/s 13.0K IO/s 8.3K IO/s

6. Dot Hill Systems Confidential / Covered under NDA 5730’s storage controller processor accounts for the higher sequential write transaction performance both Active/Active and failed over. 5730 sustains between 150% and 220% higher write transaction performance than 2730T at deeper queued small block host request sizes. 2730T vs. 5730 in RAID 5 & 6 RAID 5 & 6 Sequential Write with 48 drives

7. Dot Hill Systems Confidential / Covered under NDA 2730T vs. 5730 in RAID 5 & 6 RAID 5 & 6 Sequential READ with 48 drives 5730 controller read bandwidth is 800MB/s per controller versus 2730T peaking at 570MB/s. 5730 sustains 40% higher read throughput then 2730T at large block sizes. The Active/Active 5730 read performance in the curve is limited by the four port FC host. 5730 Active/Active read performance can sustain 1600MB/s with multiple host systems accessing.

8. Dot Hill Systems Confidential / Covered under NDA 5730 Scalability Testing (24 – 60 Drives) Active/Active Controller Random Read/Write Drive numbers have a much larger affect on random performance. For reads there is almost a direct correlation between the total number of drives accessed and the total random transaction IOPS. The drive random access performance is the limiting factor for reads in general. Writes top out at 48 drives. Additional drives won’t improve random write numbers. The limit becomes the controller processing and cache algorithm.

9. Dot Hill Systems Confidential / Covered under NDA 5730 Max Configuration (108 Drive) Sequential Reads/Writes for Active/Active (Throughput & IOPS) The RAID50 VDisk in this configuration is 27-drives, with 3 sub-arrays of 9-drive RAID5. In this test configuration two dual port host systems are connected through the switch to 5730. Each host accesses the 4 LUNs presented by the 5730 Active/Active RAID system. Each host issues a queue depth / LUN, therefore each LUN sees 2x the total queue depth of each host.