💾 Storage infrastructure
Storage types
| Type |
Description |
Latency |
Use case |
| DAS (Direct Attached) |
Disks directly in server |
<0.1 ms |
OS, cache, local data |
| SAN (Storage Area Network) |
Block devices over network |
<1 ms |
Databases, VM datastores |
| NAS (Network Attached Storage) |
File access (NFS, SMB) |
1-3 ms |
Shared files, home dirs |
| Object storage |
REST API, flat namespace |
10-100 ms |
Backups, media, big data |
Protocols
| Protocol |
Type |
Speed |
Note |
| Fibre Channel |
SAN |
8/16/32/64 Gbps |
Low latency, dedicated network |
| iSCSI |
SAN (IP) |
1/10/25 GbE |
Cheaper, over ethernet |
| NVMe-oF |
SAN (NVMe) |
25/50/100 GbE |
Lowest latency, emerging |
| NFS |
NAS |
1/10/25 GbE |
Universal, simple |
| SMB/CIFS |
NAS |
1/10/25 GbE |
Windows native |
| S3 API |
Object |
— |
Standard for object storage |
RAID
| RAID |
Min. disks |
Capacity |
Protection |
Read speed |
Write speed |
Use case |
| 0 |
2 |
100 % |
None |
N × (striping) |
N × |
Temp data, cache (risky) |
| 1 |
2 |
50 % |
1 disk |
N × (mirror) |
1 × |
OS disk, critical data |
| 5 |
3 |
67-94 % |
1 disk |
N-1 × |
N-1 × (parity write penalty) |
Universal file/VM storage |
| 6 |
4 |
50-88 % |
2 disks |
N-2 × |
N-2 × (double parity) |
Large capacities, important data |
| 10 |
4 |
50 % |
1/mirror |
N × |
N/2 × |
Databases, VM, high-performance |
| 50 |
6 |
67-94 % |
1/stripe |
N-1 × |
N-1 × |
Large capacity + performance |
| 60 |
8 |
50-88 % |
2/stripe |
N-2 × |
N-2 × |
Enterprise |
Stripe size
- Small stripe (16-64 KB) — better IOPS, worse throughput (databases, OLTP)
- Large stripe (128-1024 KB) — better throughput, worse IOPS (video, media, backup)
- Write hole on RAID 5/6: metadata inconsistency during power loss while writing parity (prevention: non-volatile cache, battery-backed RAID controller)
Software-Defined Storage (SDS)
| Tool |
Type |
Use case |
| Ceph |
Object/Block/File (RADOS) |
Universal SDS, OpenStack, Kubernetes |
| MinIO |
Object (S3 API) |
High-performance S3, AI/ML data lake |
| GlusterFS |
Distributed File |
Shared filesystem, POSIX |
| Longhorn |
Block (Kubernetes) |
K8s PVC, microservices |
| Linstor |
Block (DRBD + LVM) |
Linux SDS, Kubernetes |
| VMware vSAN |
Block (HCI) |
VMware ecosystem |
| StarWind |
Block (HCI) |
Hyper-V / VMware |
Ceph
Architecture:
CRUSH map (Controlled Replication Under Scalable Hashing):
- Algorithm for calculating data placement (no central index)
- Layers: Root → Datacenter → Rack → Host → OSD
- Failure domain: replication across racks / hosts
ceph osd crush rule create-replicated replicated_rule default host
Access interfaces:
| Interface |
Type |
Use case |
| RBD (RADOS Block Device) |
Block |
VM images, Kubernetes PVC (csi-rbd) |
| RGW (RADOS Gateway) |
Object (S3/Swift API) |
S3-compatible storage, backup |
| CephFS |
File (POSIX) |
Shared filesystem, home dirs |
| NFS-Ganesha |
File (NFS) |
NFS export over CephFS |
Erasure coding:
- K+M (data + parity chunks), e.g. 8+3 (8 data, 3 parity)
- More space-efficient than 3× replication (1.375× vs 3×)
- Higher CPU overhead, lower IOPS
- Recommended for cold data (RGW) instead of replication
Enterprise storage vendors
Hitachi VSP (Virtual Storage Platform)
| Model |
Architecture |
Max capacity |
IOPS / Latency |
Protocols |
Use case |
| VSP 5200/5600 |
Active-active, scale-up/out, 2–12 controllers |
69.3 PB raw, 287 PBe |
33M IOPS, 39 µs |
FC-NVMe 32Gb, FC 16/32Gb, FICON 16Gb, iSCSI 10Gb |
Mission-critical, mainframe, enterprise consolidation |
| VSP E590/E790/E1090 |
Symmetric active-active, up to 65 nodes/130 controllers |
10.62 PB raw (E1090) |
8.4M IOPS, <41 µs |
FC 32Gb, iSCSI 25Gb, FC-NVMe 32Gb |
Midrange enterprise, hybrid workloads |
Key features: SVOS common across entire portfolio, AI-driven data reduction 4:1 guarantee, Global-Active Device metro clustering, 8 nines availability (HW), 100% data availability guarantee.
Huawei OceanStor Dorado
| Model |
Architecture |
Max capacity |
IOPS / Latency |
Protocols |
Use case |
| Dorado 8000/18000 V6 |
SmartMatrix full-mesh, up to 32 controllers |
32 TB cache, 6400 SSD |
40M IOPS, 0.05 ms |
FC 32/64Gb, FC-NVMe, iSCSI, NFS, SMB, NVMe/RoCE, S3 |
Mission-critical, finance, govt, carrier |
| Dorado 8000/18000 V7 (2025) |
SmartMatrix 4.0, up to 64/128 controllers |
500 PB+ |
>100M IOPS, 0.03 ms |
FC, RoCE, NVMe/TCP, NFS, SMB, S3 |
AI workloads, converged block/file/object |
Key features: SmartMatrix survives 7/8 controllers, FlashEver (3-gen online HW upgrade in 10 years), RAID-TP (triple SSD failure), DPU-based SmartNIC, ML-based I/O prefetch, 100% ransomware detection (Tolly), #1 SPC-1 benchmark.
Dell PowerStore & PowerMax
| Model |
Architecture |
Max capacity |
IOPS / Latency |
Protocols |
Use case |
| PowerStore 1500/5500/9500 (Gen 3) |
Active-active dual-node, PCIe Gen5, DDR5, RDMA 200GbE |
1.2 PB raw, 5.8 PBe |
3× IOPS vs Gen2 |
FC 32/64Gb, iSCSI, NVMe/FC, NVMe/TCP, NFSv4, SMB3 |
Midrange-to-high-end, VMware, containerized |
| PowerMax 2500/8500 |
Scale-out NVMe, Dynamic Fabric, up to 16 nodes |
8.8 PBe (2500), 18 PBe (8500) |
6 nines availability |
FC 64Gb, FICON, NVMe/FC, NVMe/TCP, iSCSI, NFS, SMB |
Mission-critical, mainframe, OLTP, cyber vault |
Key features: PowerStore 6:1 DRR guarantee, unified block/file/vVols out of box, Cyber Detect AI anomaly; PowerMax 5:1 DRR, Secure Snapshots 65M, SRDF/Metro, Flexible RAID up to 92% efficient, FIPS 140-3.
HPE Alletra
| Model |
Architecture |
Max capacity |
IOPS / Latency |
Protocols |
Use case |
| Alletra 5000 |
Active-active hybrid flash, dual controller |
1.2 PB raw |
99.9999% guarantee |
FC, iSCSI |
Mixed primary + secondary, cost-efficient hybrid |
| Alletra 6000 |
Active-active all-NVMe, dual controller |
~368 TB usable |
<100 µs |
FC, iSCSI |
Business-critical DB, VDI, VMware |
| Alletra 9000 |
Active-active all-NVMe, multi-node scale-out |
2–4 PB+ usable |
~2–3M IOPS, <150 µs |
FC, iSCSI, NVMe/FC |
Mission-critical ERP, AI, consolidation |
| Alletra Storage MP |
Disaggregated modular, block + file + object |
5.8 PB block, 11.8 PB object |
100% availability guarantee |
FC, iSCSI, NVMe/FC, NFS, SMB, S3 |
Multi-protocol consolidation, AI/analytics |
Key features: Triple Parity RAID (5000), InfoSight AI Ops, HPE GreenLake as-a-service, non-disruptive controller upgrades (MP), 100% data availability guarantee.
Infinidat
| Model |
Architecture |
Max capacity |
IOPS / Latency |
Protocols |
Use case |
| InfiniBox SSA G4 |
Triple-active controller, AMD EPYC PCIe 5.0, DDR5 |
1.97 PB usable / 5.9 PBe |
2.24M IOPS, 35 µs |
FC 32Gb, 25/100GbE, NVMe-oF/TCP, iSCSI, NFS, SMB, S3 |
Mission-critical Oracle/SQL, multi-site DR |
| InfiniBox G4 Hybrid |
Triple-active hybrid (HDD + flash cache) |
10.9 PB raw / 32.8 PBe |
2.24M IOPS, 64 GB/s |
FC, Ethernet, NVMe-oF, iSCSI, NFS, SMB, S3 |
Backup, massive unstructured data |
Key features: Only 3-way active on the market, Neural Cache (ML-driven), InfiniRAID, Immutable snapshots, 100% availability + 1-min snapshot recovery guarantee, everything included in base price (no extra licensing).
Pure Storage FlashArray
| Model |
Architecture |
Max capacity |
IOPS / Latency |
Protocols |
Use case |
| FlashArray//X (X20–X90 R5) |
Active-active, NVMe DirectFlash |
1.2 PB raw / 4.4 PBe |
250 µs, 5:1 DRR |
FC, NVMe/FC, NVMe/RoCE, NVMe/TCP, iSCSI, NFS, SMB |
Mission-critical DB, VMware, enterprise |
| FlashArray//C (C50–C90 R5) |
Active-active, QLC DirectFlash |
4.2 PB raw / 16.3 PBe |
5:1 DRR |
FC, NVMe-oF, iSCSI, NFS, SMB |
Capacity-optimized, backup, file |
| FlashArray//XL (XL190) |
Active-active, 40 DirectFlash modules |
1.9 PB raw / 9.4 PBe |
>4M IOPS, <100 µs, 45 GB/s |
FC 64Gb, 100GbE RoCE, NVMe/FC, NVMe/TCP, NFS, SMB |
Largest DB consolidation, OLTP |
Key features: DirectFlash (no FTL layer), 99.9999% availability, Evergreen (never forklift upgrade), Purity OS unified across entire portfolio, ActiveCluster/ActiveDR, Pure1 AIOps.
Lenovo ThinkSystem
| Model |
Architecture |
Max capacity |
IOPS / Latency |
Protocols |
Use case |
| DM Series (DM3200F/5200F/7200F) |
Active-active, all-NVMe, NetApp ONTAP |
1.8 PB raw / 6.8 PBe |
Up to 120 NVMe SSD |
FC 64Gb, iSCSI, NVMe/FC, NFS, SMB, S3 |
Unified block/file, AI/ML, VMware |
| DG Series (DG5200/7200) |
Active-active, all-QLC, ONTAP |
7.4 PB raw / 27 PBe |
QLC economics |
FC, NVMe/FC, NVMe/TCP, iSCSI, NFS, SMB, S3 |
Capacity-optimized, backup, archive |
| DE Series (DE4000F–DE6600F) |
Active-active, SAS/NVMe hybrid |
1.84 PB raw |
2M IOPS, <100 µs, 44 GB/s |
FC 32Gb, iSCSI 25Gb, NVMe/FC, SAS, NVMe/RoCE |
HPC, analytics, video surveillance |
Key features: DM/DG use ONTAP (SnapMirror, SnapVault, FabricPool, RAID-DP/RAID-TEC); cluster scale-out up to 12 HA pairs; DE series best price/performance in portfolio.
Synology
| Model |
Architecture |
Max capacity |
Protocols |
Use case |
| UC3200/UC3400 |
Active-active dual-controller, SAS backend |
576 TB raw |
iSCSI, FC 16Gb, 10/25GbE |
SMB/midmarket SAN, VMware, HA |
| DS/RS Series (RS3626xs+, RS6426xs+) |
Single-controller / HA pair, Btrfs |
864 TB raw, 1 PB volume |
SMB, NFS, iSCSI, FC (HBA) |
SME all-in-one NAS/SAN, backup, surveillance |
Key features: DSM UC for SAN, Synology HA, Snapshot Replication (16K snapshots), VMware VAAI/ODX/ALUA, Surveillance Station, low TCO.
Vendor comparison — overview
| Vendor |
Flagship |
Max IOPS |
Max capacity |
Latency |
Availability guarantee |
Main differentiator |
| Hitachi |
VSP 5600 |
33M |
287 PBe |
39 µs |
8 nines (HW) |
Mainframe + open; 65-node cluster |
| Huawei |
Dorado 18000 V7 |
>100M |
500 PB+ |
0.03 ms |
99.99999% |
SmartMatrix; #1 SPC-1 |
| Dell |
PowerMax 8500 |
— |
18 PBe |
— |
6 nines |
SRDF/Metro; mainframe |
| HPE |
Alletra 9000/MP |
~3M |
11.8 PBe |
<150 µs |
100% data guarantee |
InfoSight AIOps; GreenLake |
| Infinidat |
InfiniBox SSA G4 |
2.24M |
32.8 PBe |
35 µs |
100% availability |
3-way active; Neural Cache |
| Pure |
FlashArray//XL |
>4M |
16.3 PBe |
<100 µs |
99.9999% |
DirectFlash; Evergreen |
| Lenovo |
DM7200F |
— |
27 PBe |
— |
— |
ONTAP ecosystem; broad portfolio |
| Synology |
UC3400 |
690K |
576 TB |
— |
— |
Lowest price for active-active SAN |
Storage selection by use case
| Use case |
Recommendation |
Rationale |
| Mainframe + open hybrid |
Hitachi VSP / Dell PowerMax |
Only ones with FICON + FC simultaneously |
| AI/ML training |
Huawei Dorado V7 / Pure //XL |
Highest IOPS, lowest latency |
| Enterprise DB (Oracle, SQL Server) |
Infinidat / Pure //X |
Low latency, consistent performance |
| Virtualization (VMware, Hyper-V) |
Dell PowerStore / HPE Alletra 6000 |
VAAI, vVols, InfoSight |
| SMB / SME |
Synology / Lenovo DE |
Low TCO, simple management |
| Object storage / backup |
Pure //C / Lenovo DG / Infinidat Hybrid |
QLC economics, high capacity |
| Multi-protocol consolidation |
HPE Alletra MP / Huawei Dorado |
Block + file + object in one platform |
Decision diagram — storage platform selection
OpenStack Storage
OpenStack offers three main storage services:
| Service |
Type |
Description |
| Cinder |
Block storage |
Persistent volumes for instances (iSCSI, NFS, Ceph RBD) |
| Swift |
Object storage |
RESTful object store (S3-compatible via middleware) |
| Manila |
File storage |
Shared file systems (NFS, CIFS) as a managed service |
Cinder (Block Storage)
- Multi-backend support: LVM, Ceph RBD, NFS, iSCSI, Fibre Channel
- Snapshoting, cloning, encryption at rest
- Cinder scheduler for volume distribution across backends
- QoS specs for IOPS/bandwidth limits
Swift (Object Storage)
- Alternative to S3 for on-prem object storage
- Ring-based data distribution (consistent hashing)
- Multi-region replication (syncopy)
- Stateless REST API (RESTful, no single point of failure)
Manila (Shared File Systems)
- Managed NFS/CIFS for sharing between instances
- Backends: NetApp, Dell EMC, CephFS, GlusterFS
- Access rules (IP-based, cert-based, user-based)
- Use case: HPC cluster home directories, NAS for legacy apps
Container storage (OpenStack + Ceph)
Ceph is the most common storage backend for OpenStack: Cinder (RBD), Swift (RGW), Manila (CephFS), Glance (RBD images).
Sources
Links, books and standards: sources/infrastructure/sources.md
Recommended reading
| Book |
Authors |
ISBN |
Description |
| Storage Systems |
Ganger, Gibson |
978-1680837540 |
Textbook covering the design, implementation and operation of storage systems — from device characteristics through OS, databases and networking to server distribution and large-scale systems. An essential resource for storage infrastructure architects. |
Last revision: 2026-06-03