WeRecoverData

Dell PowerScale and EMC Isilon Data Recovery

PowerScale — still widely known by its original name, Isilon — is a scale-out NAS cluster where a single OneFS file system spans every node. That design means a data-loss event is rarely confined to one disk: losing more nodes or drives than the configured protection level, or damaging OneFS metadata, affects the whole namespace.

Platform Lineage and Naming

Isilon Systems shipped the first OneFS clusters in the early 2000s and was acquired by EMC in 2010. The line ran as EMC Isilon and then Dell EMC Isilon through the S-Series, X-Series, NL-Series and HD-Series generations.

In 2020 Dell rebranded the family as PowerScale, introducing PowerEdge-based F-Series all-flash, H-Series hybrid and A-Series archive nodes while keeping OneFS as the file system. Isilon Gen6 chassis (F800/H600/A200 and similar) and PowerScale nodes commonly coexist in the same cluster, and older Gen5 Isilon nodes are still in service.

Generations and Models We Evaluate

Architecture and Data Layout

OneFS presents a single file system and single namespace across all nodes in the cluster. Files are striped across nodes with FEC-based protection, and file metadata (inodes, LINs, the B-tree structures OneFS uses) is itself distributed. There is no per-node file system you can mount independently.

Because protection is expressed per file or per directory (for example +2d:1n, +3d:1n1d, +2n), the survivability of a given dataset depends on the protection policy applied to it at the time of failure, not on a single cluster-wide RAID level.

SmartPools tiering, SmartDedupe, snapshots and SyncIQ replication add further layers of indirection. A recovery frequently means rebuilding the OneFS layout from the surviving node drives and then extracting files from the reconstructed namespace.

Logical Failures

Hardware Failures

Encryption and Keys

PowerScale and Isilon nodes are available with self-encrypting drives and cluster key management. If SEDs are in use, the node's key state must be preserved — drives pulled from an SED node without the cluster key material cannot be read.

Frequently Asked Questions

Our cluster lost more nodes than the protection level allows. Is anything recoverable?

Partial recovery is often possible. Files whose stripes and metadata survive on the remaining nodes can frequently be reconstructed, while files that lost too many stripe units may be incomplete. The evaluation establishes how much of the namespace is reachable before any recovery work begins.

Do you need every node in the cluster?

We need the drives from as many nodes as still exist, plus cluster configuration data. Missing nodes reduce what can be rebuilt but do not automatically end the case.

Is Isilon the same thing as PowerScale?

Yes — PowerScale is the current name of the platform Dell EMC previously sold as Isilon. Both run OneFS, and the recovery approach is the same family of work.

A directory was deleted over SMB. Can it come back?

If a snapshot covering that path exists, restore from it first. If not, stop writes to the cluster immediately — OneFS reuses freed blocks, so continued production activity is the main threat to the deleted data.

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