This case study details the forensic restoration of a 26 GB Sybase ASE 11.0 database following a severe storage array (RAID) failure. By identifying and resolving low-level file cross-referencing, the AS Data Recovery team achieved a 100% data recovery within two hours.
Client & Data Information
- Client Name: Confidential
- Data Type: Sybase ASE 11.0 (.dat devices)
- Data Capacity: 26 GB
- Primary Issue: Disk Array (RAID) Failure / Physical File Corruption
Incident Summary
The client’s production server suffered a hardware malfunction within its disk array. While the physical disks were partially accessible, the resulting file system corruption caused cross-referencing at the sector level. In Sybase ASE terms, the pointers within the .dat database devices were pointing to incorrect physical offsets or overlapping with other files. This made it impossible to start the Sybase dataserver, as it could no longer guarantee the integrity of its internal page structure.
Technical Analysis
Upon forensic analysis of the 26 GB Sybase device files, AS Data Recovery engineers identified:
- Underlying Cross-Linking: The RAID controller had incorrectly mapped data blocks, causing segments of the Sybase data device to be overwritten or shared with other system files.
- Page Header Mismatch: Sybase ASE uses 2KB pages (in version 11.0). Our hex-level scan revealed that many page headers contained inconsistent Virtual Page Numbers (VPNs) due to the array’s mapping errors.
- Metadata Integrity: Despite the physical block errors, the syscolumns and sysobjects system tables (the database’s “brain”) were located and stabilized.
Recovery Solution
The recovery strategy focused on Logical Row Extraction from Corrupted Devices. Since the Sybase ASE engine could not safely initialize the corrupted .dat files, our engineers bypassed the engine entirely. Using proprietary forensic tools, we performed a deep-sector scan of the devices to locate and verify valid data pages. By identifying the unique object IDs (OIDs) within each page, we reassembled the table data and exported it directly into a clean, new Sybase ASE environment.
Recovery Process
- Forensic Imaging and RAID Analysis: Created a sector-by-sector clone of the corrupted array to prevent further hardware degradation.
- Device Structure Parsing: Utilized AS Data Recovery’s specialized Sybase ASE tools to analyze the 26 GB device files and identify the correct offsets for data pages, ignoring the incorrect cross-referenced pointers.
- Direct Page-to-Row Extraction: Manually scanned the pages to identify table fragments. Our tools extracted the raw rows while filtering out “noise” from the cross-linked non-database data.
- Data Migration: Reconstructed the schema in a healthy Sybase ASE instance and imported the 100% verified data.
- Final Integrity Verification: Performed a comprehensive audit of record counts and relational links, confirming total data restoration.
Recovery Results
- Recovery Integrity: 100% (All table data fully restored)
- Recovered Volume: 26 GB
- System Status: Database fully operational on new storage hardware.
- Total Recovery Time: 2 Hours
Expert Reminder from AS Data Recovery: RAID corruption can lead to “silent” data overlaps that standard check utilities like dbcc checkdb cannot fix. Do not attempt to force the database online, as the engine may continue to write to cross-linked sectors, causing permanent data loss. Contact AS Data Recovery professionals immediately. We can extract data directly from .dat files regardless of array failure or metadata corruption.