DCT
1:18-cv-02027
Red Hat Inc v. Sequoia Technology LLC
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Red Hat, Inc. (Delaware)
- Defendant: Sequoia Technology, LLC (Delaware)
- Plaintiff’s Counsel: Fish & Richardson P.C.
- Case Identification: 1:18-cv-02027, D. Del., 12/19/2018
- Venue Allegations: Venue is asserted to be proper in the District of Delaware because Defendant Sequoia Technology, LLC is a resident of the district.
- Core Dispute: Plaintiff seeks a declaratory judgment that its Red Hat Enterprise Linux (RHEL) operating system does not infringe Defendant's patent related to logical volume management in computer storage systems.
- Technical Context: The technology concerns methods for managing logical data volumes, which virtualize physical storage disks to improve performance and flexibility, a foundational technique in enterprise-level computing and data storage.
- Key Procedural History: The complaint notes that this declaratory judgment action was filed in response to Defendant Sequoia having instituted four separate patent infringement lawsuits in the same district against customers of Plaintiff Red Hat. Sequoia’s infringement allegations in those cases reportedly rely on the functionality of Red Hat’s RHEL software.
Case Timeline
| Date | Event |
|---|---|
| 2001-07-27 | ’436 Patent Priority Date |
| 2004-04-06 | ’436 Patent Issue Date |
| 2005-02-01 | Red Hat Enterprise Linux (RHEL) version 4 released |
| 2018-07-31 | Sequoia files infringement suits against Dell, Hitachi, and HPE |
| 2018-08-23 | Sequoia files infringement suit against Super Micro Computer |
| 2018-12-19 | Red Hat files Complaint for Declaratory Judgment |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,718,436 - Method for managing logical volume in order to support dynamic online resizing and software RAID and to minimize metadata and computer readable medium storing the same, issued April 6, 2004
The Invention Explained
- Problem Addressed: The patent describes the limitations of prior art logical volume managers. Conventional methods used a fixed mapping function to convert a logical address to a physical disk address, which limited flexibility for services like "online resizing" (changing volume size without downtime). Other table-based methods suffered from having metadata that was too large, which delayed system booting and consumed excessive memory. (’436 Patent, col. 3:27-46).
- The Patented Solution: The invention proposes a method for managing logical volumes that uses a separate, modifiable "mapping table" to relate logical addresses to physical addresses, rather than a fixed function. (’436 Patent, col. 4:40-49). This architecture is designed to support dynamic resizing and various RAID configurations while minimizing the amount of metadata needed, which is achieved in part by dividing the mapping table and storing parts of it across different disk partitions. (’436 Patent, col. 9:8-14).
- Technical Importance: The described approach aims to provide the flexibility of table-based volume management without the performance penalties of large metadata overhead, a key challenge in designing scalable and efficient enterprise storage systems. (’436 Patent, col. 4:50-63).
Key Claims at a Glance
- The complaint identifies independent claims 1, 8, and 11, and dependent claims 3, 7, and 14, as being at issue based on allegations in related customer lawsuits. (Compl. ¶¶ 33-36).
- Independent Claim 1 (Method):
- creating a logical volume by gathering disk partitions
- generating metadata including a disk partition table, a logical volume table, an extent allocation table, and a mapping table
- storing the metadata on the disk partitions
- dynamically resizing the logical volume and modifying the metadata
- calculating and returning a physical address from a logical address using the mapping information
- The complaint notes that Sequoia has asserted at least method claims 1 through 3 in its related cases. (Compl. ¶22).
III. The Accused Instrumentality
Product Identification
- Red Hat Enterprise Linux (RHEL) operating systems, versions 4 and later. (Compl. ¶1).
Functionality and Market Context
- RHEL is a widely-used, Linux-based operating system targeted at the commercial market. (Compl. ¶12). It is a form of free and open-source software ("FOSS"), where the source code is made available to users. (Compl. ¶11). Red Hat derives revenue from services surrounding RHEL, such as aggregation, certification, testing, and support. (Compl. ¶13). The complaint alleges that Sequoia's infringement theories in parallel litigation against Red Hat customers are based exclusively on citations to Red Hat's public-facing technical publications, such as the "Red Hat Enterprise Linux 5 Logical Volume Manager Administration LVM Administrator's Guide." (Compl. ¶¶ 23-24).
- No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint seeks a declaratory judgment of non-infringement. The following table summarizes Red Hat's specific allegations of how its RHEL product does not meet the limitations of the asserted claims.
’436 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Non-Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method for managing a logical volume in order to support...minimizing a size of metadata | RHEL does not include a method for managing a logical volume in order to support minimizing a size of metadata. | ¶34 | col. 12:16-19 |
| a) creating the logical volume by gathering disk partitions... | RHEL does not "creat[e] [a] logical volume by gathering disk partitions." | ¶33 | col. 12:20-22 |
| wherein the metadata includes...a mapping table for maintaining a mapping information for a physical address space... | RHEL does not include "a mapping table for maintaining a mapping information for a physical address space." | ¶35 | col. 12:45-49 |
Identified Points of Contention
- Factual Question: A central factual dispute will concern the actual architecture of RHEL's Logical Volume Manager (LVM). The case will turn on whether RHEL's implementation for creating and managing volumes is functionally the same as the claimed method of "gathering disk partitions." (Compl. ¶33).
- Scope Question: The analysis will question whether the data structures used by RHEL to manage volume layouts constitute a "mapping table" as that term is used in the patent. Red Hat's position suggests its own data structures are technically distinct from the claimed "mapping table." (Compl. ¶35).
- Functional Question: A further question is whether RHEL's functionality, taken as a whole, can be characterized as a method for "minimizing a size of metadata" as required by the claim preamble. (Compl. ¶34). This may depend on whether the preamble is found to be a limiting part of the claim.
V. Key Claim Terms for Construction
The Term: "creating the logical volume by gathering disk partitions"
- Context and Importance: This term from step (a) of claim 1 describes the fundamental action of forming a logical volume. Red Hat’s explicit denial that RHEL performs this step makes its definition critical. (Compl. ¶33). Practitioners may focus on whether "gathering disk partitions" implies a specific technical mechanism that differs from how RHEL's LVM composes volumes.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes a logical volume as a "union of disk partitions" and states it "includes more than one disk partition," which may support a broader reading of "gathering" as simply combining or uniting partitions. (’436 Patent, col. 6:60-65).
- Evidence for a Narrower Interpretation: The detailed description of volume creation involves initializing a metadata table on "each disk partition used to construct the logical volume," which could suggest "gathering" is a specific process tied to this metadata initialization step. (’436 Patent, col. 10:8-12).
The Term: "mapping table"
- Context and Importance: This data structure is a core component of the claimed invention, and Red Hat's denial that RHEL includes such a table makes its construction central to the infringement analysis. (Compl. ¶35). The dispute will likely focus on whether the data structures RHEL does use for address translation are structurally and functionally equivalent to the claimed "mapping table."
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The summary of the invention describes the object as providing a manager "using a mapping table storing a relation between a physical address and a logical address," which could be read broadly to cover various forms of address-translation data structures. (’436 Patent, col. 4:1-4).
- Evidence for a Narrower Interpretation: The patent provides specific details about its mapping table, stating it includes "a pair of PP ID 102 and Extent Number 103 per each extent for continuous logical address space." (’436 Patent, col. 8:56-59; Fig. 6). This detailed structure could support a narrower definition that requires these specific paired elements.
VI. Other Allegations
Indirect Infringement
- Red Hat seeks a declaratory judgment that it has not induced or contributed to the infringement of the ’436 Patent by others. (Compl. ¶¶ 1, 28). The complaint states that Red Hat has a reasonable apprehension of being sued for indirect infringement based on Sequoia’s allegations against its customers, which rely on the functionality enabled by RHEL and documented in Red Hat’s administrator guides. (Compl. ¶¶ 24, 26-27). The specific facts alleged to support potential claims of inducement would be the provision of RHEL software along with technical documentation that allegedly instructs users on how to perform infringing actions. (Compl. ¶26).
Willful Infringement
- The complaint does not contain allegations related to willful infringement.
VII. Analyst’s Conclusion: Key Questions for the Case
This declaratory judgment action appears to hinge on a small number of core technical and legal questions:
- A primary issue will be one of technical implementation: Does the architectural design of Red Hat’s Logical Volume Manager (LVM) in RHEL align with the specific method claimed in the ’436 Patent? The case will likely require a deep dive into whether RHEL's method of composing volumes is equivalent to "gathering disk partitions" and whether its address translation data structures are equivalent to the patent’s "mapping table."
- A second key question will be one of evidentiary basis: Sequoia’s infringement theory, as characterized by Red Hat, relies on statements in Red Hat’s own technical manuals. The court will have to determine if these public documents accurately describe a system that practices the patented method, or if there is a mismatch between the documentation and the actual operation of the RHEL source code.
- Finally, a question of claim scope will be central: Can the term "mapping table", as defined by the patent’s specification and figures, be construed broadly enough to read on the data management structures within RHEL, or is it limited to the specific paired-element structure disclosed in the patent?