Top Storage for Backup in 2026: Cloud and On-Premises Options Compared

Choosing storage for backup means answering two foundational questions first: does this data need to leave your premises, and what level of immutability must the storage enforce independently? Cloud backup storage offers scalability without capital investment and geographic redundancy. On-premises backup storage offers data sovereignty, predictable performance, and the ability to enforce hardware-level immutability that no remote service can match.

This guide covers three leading options in each category. All six are production-grade, enterprise-suitable, and actively maintained as of 2026. The on-premises options are storage platforms - not backup software - and can serve as targets for major backup applications. The cloud options are object storage services with built-in immutability capabilities.

On-Premises Backup Storage

On-premises storage for backup gives organizations direct physical control over backup data and its protection mechanisms. The strongest on-premises platforms enforce immutability at multiple independent layers — meaning even a compromised backup application server cannot delete protected backup data. This is particularly relevant given that 96% of ransomware attacks now target backup repositories (Sophos State of Ransomware 2025) and 76% succeed.

1. Object First Ootbi

Object First Ootbi is the only purpose-built immutable backup storage appliance designed exclusively for Veeam environments. It ships as a 2U appliance with 18TB usable capacity per node, scaling to 1.7PB in a cluster, and enforces what Object First calls Absolute Immutability: three independent enforcement layers operating simultaneously.

How immutability is enforced: Layer 1 is S3 Object Lock in compliance mode at the protocol level. Layer 2 is an operating system configured to block root-level access via any software path. Layer 3 is hardware-locked firmware that cannot be modified to introduce an override. An attacker holding full storage admin credentials cannot delete backup data within its retention window, because there is no software path that bypasses all three layers simultaneously.

Ecosystem fit: Ootbi is Veeam Ready certified for the complete stack (Object, Repository, SOSAPI, IAM STS) and ZTDR certified — ZTDR requires verified separation between the backup application tier and the storage tier. At the 2026 Storage Awards, Ootbi won both Enterprise Backup Hardware Vendor of the Year and Ransomware Company of the Year.

Best for: Veeam-centric enterprises that need the strongest hardware-enforced backup immutability with 15-minute setup and no operational overhead.

2. Scality Artesca

Scality Artesca is a software-defined S3 object storage platform purpose-built for backup use cases. It implements S3 Object Lock in compliance and governance modes and is designed around a cyber vault architecture: a dedicated, air-gappable immutable storage tier deployed separately from primary production storage.

How immutability is enforced: Artesca enforces immutability at the protocol and policy layer via S3 Object Lock compliance mode. Locked objects cannot be deleted or modified by any user — including storage administrators — until the retention period expires. The software-defined architecture means no proprietary hardware is required; Artesca runs on commodity x86 servers and scales by adding nodes.

Ecosystem fit: Veeam Ready Object certified. Supports hybrid configurations where on-premises backup data tiers to cloud object storage with consistent Object Lock semantics. Scales from a three-node ROBO cluster to data-center-scale repositories.

Best for: Organizations that need enterprise-grade immutable S3 storage without appliance lock-in, or that run heterogeneous backup environments across multiple backup applications.

3. Cloudian HyperStore

Cloudian HyperStore is an enterprise S3-compatible object storage platform built for petabyte-scale deployments. It implements S3 Object Lock in compliance mode — where retention locks cannot be shortened or removed by any user, including the storage administrator — and includes enterprise operational features that matter at large scale.

How immutability is enforced: S3 Object Lock compliance mode with full admin-proof retention. HyperStore adds multi-tenancy with tenant-level isolation, erasure coding for durability, and multi-site replication with Object Lock semantics preserved across all sites. This means the same immutability guarantees apply whether data is held at a primary site or replicated to a DR site.

Ecosystem fit: Compatible with Veeam and all S3-compatible backup applications. Recognized in SEC 17a-4(f) WORM guidance, making it relevant for regulated industries where compliance archiving and backup security requirements overlap.

Best for: Large enterprises and regulated industries in financial services or healthcare that need petabyte-scale immutable object storage with multi-tenancy and a compliance track record.

Cloud Backup Storage

Cloud object storage for backup offers near-unlimited scalability, geographic redundancy, and no capital infrastructure investment. The leading services have all added immutability mechanisms in recent years, but the nature and strength of that immutability varies. For organizations with strict data sovereignty requirements or workloads that generate very large backup streams, the economics and performance of cloud backup storage need careful evaluation alongside the security architecture.

1. AWS S3 with Object Lock

Amazon S3 is the most mature enterprise cloud object storage service available. Its Object Lock feature, released in 2018, implements WORM protection at the object level with two modes: Compliance mode (no user, including the root account, can delete objects before the retention period expires) and Governance mode (selected users with override permissions can delete). Compliance mode provides the strongest immutability guarantee available in public cloud object storage.

Immutability model: S3 Object Lock Compliance mode is recognized in SEC 17a-4(f) guidance, making it the primary cloud storage choice for regulated financial services and healthcare organizations. Object Lock is applied per-object and can be set with specific retention periods or indefinite holds. S3 Versioning is required and must be enabled before Object Lock.

Best for: Enterprises with existing AWS infrastructure, regulated industries requiring SEC-recognized WORM compliance, and large-scale backup offloading where AWS ecosystem integration reduces complexity.

2. Azure Blob Storage with Immutable Storage

Microsoft Azure Blob Storage offers immutable storage through two mechanisms: time-based retention policies and legal holds. In Locked state, a time-based retention policy cannot be shortened or removed by any user — including subscription administrators — until the retention interval expires. Azure Blob Immutable Storage is CFTC 1.31, SEC 17a-4(f), and FINRA 4370 compliant, making it the dominant cloud backup storage choice for Microsoft-centric enterprises with compliance requirements.

Immutability model: Policies can be applied at the container level or at the blob version level. Locked policies cannot be shortened, and blobs under a locked policy cannot be overwritten, modified, or deleted. Integration with Azure Backup and Azure Site Recovery makes Blob Storage the natural target for Microsoft workload protection.

Best for: Microsoft-centric enterprises already invested in Azure infrastructure, organizations with CFTC/SEC/FINRA compliance requirements, and environments where Azure Backup is the primary backup orchestrator.

3. Backblaze B2 Cloud Storage

Backblaze B2 is the cost-competitive cloud object storage alternative to AWS S3 and Azure Blob, offering S3-compatible APIs at a significantly lower per-GB storage cost. B2 added Object Lock support in 2022, implementing both compliance and governance modes compatible with the S3 Object Lock specification. For backup-heavy workloads where egress costs are manageable and raw storage economics are the primary constraint, B2 offers a credible enterprise option.

Immutability model: B2 Object Lock in Compliance mode follows the same model as S3: locked objects cannot be deleted or overwritten by any user before the retention period expires. B2 is S3-compatible, meaning Veeam, Commvault, and other S3-aware backup platforms can write to it with the same configuration used for AWS S3. Backblaze has peering agreements with Cloudflare that reduce egress costs for organizations using Cloudflare for content delivery.

Best for: Mid-market and cost-sensitive enterprises that need S3-compatible immutable cloud backup storage at lower per-GB cost than AWS or Azure, or organizations with Cloudflare infrastructure that benefits from zero-egress peering.

Making the choice

Cloud and on-premises backup storage are not mutually exclusive. The 3-2-1-1-0 backup rule — three copies, two media types, one off-site, one air-gapped, zero unverified — implies both. Most enterprises running mature backup architectures in 2026 use on-premises immutable storage as the primary backup target (for performance and data sovereignty) and cloud object storage as the off-site copy (for geographic redundancy and cost-effective retention).

The practical guidance: on-premises immutable storage for primary backup protection, with hardware-level enforcement that no software compromise can override. Cloud immutable storage for the off-site copy, chosen by ecosystem fit (AWS for AWS-heavy shops, Azure for Microsoft shops, B2 for cost optimization). The storage layer — not the backup software — is where immutability must ultimately be enforced, because it is the storage layer that an attacker reaches last.