SAN (Storage Area Network) Failure
A SAN failure rarely means a single thing went wrong. It usually means a failure occurred somewhere in a stack of several layers — physical disks, a RAID or erasure-coding layer, LUN presentation, and often a file system or database on top of that — and recovery starts with figuring out which layer actually broke.
What's actually happening
A Storage Area Network presents "LUNs" (logical units) to servers as if they were plain disks, but underneath, a SAN controller manages pooled physical drives through its own RAID or erasure-coding scheme, its own caching and metadata layer, and often deduplication or thin-provisioning logic specific to that vendor. A failure can originate at any layer — a controller malfunction, a firmware bug during an update, multiple physical disk failures exceeding what the underlying redundancy tolerates, or corruption introduced by the SAN's own management software — and each layer requires different expertise to diagnose and reverse.
How recoverable this really is
Depends entirely on which layer failed, and how far that's already been compounded by follow-up troubleshooting. A controller or metadata-layer problem with the physical disks intact is often very recoverable; extensive physical disk loss beyond the array's redundancy is a fundamentally harder problem, similar in kind to the harder end of RAID array failure but at a larger scale, with vendor-specific complexity layered on top.
The general approach
Start by preserving the current state and documenting the storage stack: controller status, disk/member state, pool or RAID layout, LUN mappings, thin-provisioning and snapshot configuration, recent events, and any cache or power-loss condition. Vendor diagnostics can be extremely useful, but they should be collected without accepting reinitialization, rebuild, firmware, or destructive repair actions. If reconstruction is required, platform-specific knowledge may be necessary because allocation maps, metadata, deduplication, thin provisioning, and controller behavior can be proprietary.
Don't reinitialize pools or LUNs, force failed members online, start an uncertain rebuild, clear configuration metadata, or apply firmware simply as a troubleshooting experiment. Some automated recovery actions are normal for a healthy redundant system, but once the storage state is inconsistent, every write-capable action should be evaluated against the possibility that the current metadata and member set are no longer trustworthy.
Enterprise SAN recovery is generally beyond both consumer recovery software and a single-drive imaging setup — it usually means engaging a lab or the vendor's own team, built for exactly this kind of multi-layer failure. See our directory of major physical recovery providers; several of the larger networks specifically list enterprise SAN/NAS recovery among their services.
This page describes the general situation, not a guaranteed fix for your specific case. If you'd rather have someone experienced take a look before you try anything, see what a hands-on evaluation looks like.