A major company experienced a storage system failure and required data recovery. The storage system was purchased from one of major vendors, however it was 4 years old and not under support contract. The storage experienced multiple disk failure and entire volume wasn’t accessible. Any troubleshooting that was performed previously didn’t give results.
Entire storage system was used exclusively for the Oracle database and recovery from the backup wasn’t successful.
Upon quick assessment it was decided to attempt data recovery from the remaining disks. The disks were numbered and removed from the storage system. The internal data structure was analysed, it was established the disks had 64 KB blocks of RAID5 span across RAID5 groups. Volume configuration in the header match storage configuration.
All disks content was copied into a temporary location. A custom program was written to reconstruct data from all disk dumps into the volume. The volume was mounted into Oracle ASM with database mounted. Lost disks turned out to be a part of database index, so production data was not affected. A backup was done, followed by restore into a permanent location.
Post incident report was written and recommendations provided.
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