Misc

Unified storage product guide: Multiprotocol NAS and SAN in one storage subsystem

Unified storage incorporates network-attached storage (NAS)-style file-level and storage-area network (SAN)-style block-level access into one storage subsystem. It can also be referred to as multiprotocol storage.

Traditionally, direct-attached storage (DAS) was addressed using a single protocol, such as Server Message Block (SMB), CIFS or NFS, via a SCSI bus.

The need for a centralised storage pool drove the development of SANs, which allowed access to storage by data centre servers at the block level, still using SCSI protocols. With connectivity provided by Fibre Channel (FC), then iSCSI, central storage arrays can be accessed as if they were directly attached.

Compared with NAS using file-level access, block-level access offers the key advantage of added performance, resulting from lower file protocol overheads. This is important for such performance-critical applications as hosting virtual machines (VMs) and transaction processing with databases.

More on unified storage

Unified storage: Block-level and file-level access in one box

Unified data storage: Benefits and challenges

However, the need for more local and scalable storage that can be addressed directly by clients hasn't disappeared and has been met by file-level addressed NAS devices, typically supporting multiple file-level protocols such as SMB, CIFS and NFS, as well as IP-based protocols such as FTP and HTTP.

Now enterprises are increasingly deploying NAS devices that support both file- and block-level protocols. For our purposes, unified storage consists of a single device containing the processing unit and storage, or a rack of devices designed to work together, with the key defining factor being that the same pool of storage can be accessed at both the file and block level.

With fewer discrete components than separate SAN and NAS, unified storage can offer benefits such as lower hardware, rack space and energy requirements, along with other NAS technology benefits, including snapshots, replication and data deduplication. A key benefit for many enterprises is unified storage's single point of management.

Users raise only two drawbacks with unified storage. The first is that a single set of storage that's addressed by two protocols, although managed in one place, can appear as two systems. This can lead to mistakes, such as inadvertently attempting to back up the iSCSI-addressed SAN onto the NFS-addressed NAS. Storage management software should be smart enough to issue warnings in such cases.

The second drawback is that it can offer only NAS-style performance: The system is inherently versatile, but even block-level access may not offer the kind of performance required by transactional databases. In such scenarios, only a performance-tuned SAN fits the bill. In most cases however, unified storage offers the best of both worlds.

Here's a sample of unified storage products on the market:

BlueArc
Mercury series
Max capacity (native): 2 PB
Max ports: Six 1 GbE, two 10 GbE, four Fibre Channel
Key features: Single namespace across clusters up to eight nodes; supports iSCSI, NFS and CIFS; policy-based migration; tiered storage; thin provisioning

Titan series (two products)
Max capacity (native): 4 PB
Max ports: Two 10 GbE or six 1 GbE, eight Fibre Channel
Key features: Single namespace across clusters up to eight nodes; supports iSCSI, NFS and CIFS; policy-based migration and tiered storage across drive types; thin provisioning

Compellent Technologies
Storage Center
Max capacity (native): 720 TB
Max ports: 10 PCI slots allowing up to 12 iSCSI, up to 24 Fibre Channel, plus six 1GbE into NAS gateway
Key features: Supports iSCSI, Fibre Channel, CIFS and NFS; data deduplication; replication; snapshots; thin provisioning; automated tiered storage

EMC
Celerra NAS

NX4
Max capacity (native): 60 TB
Max ports: Four 1 Gbps, or two 10 Gbps and two 1 Gbps, plus four Fibre Channel, per blade, with maximum of two blades
Key features: Supports Fibre Channel, iSCSI, CIFS, NFS, FTP Secure and FTP; hot swap power/cooling

NS-120
Max capacity (native): 64 TB
Max ports: Eight 1 Gbps, or four 1 Gbps and four 10 Gbps, plus four Fibre Channel, per blade, with maximum of two blades
Key features: Multiprotocol SAN/NAS filer; data deduplication; thin provisioning; automated volume management

NS-480
Max capacity (native): 192 TB
Max ports: Eight 1 Gbps (copper or optical), or four copper 1 Gbps and four optical 10 Gbps, plus four Fibre Channel, per blade, with maximum of four blades
Key features: Supports multiple SANs, data deduplication and file-level retention; multiprotocol SAN gateway; addresses Fibre Channel, SATA and flash drives

NS-960
Max capacity (native): 740 TB
Max ports: Two 10 Gbps, four copper 1 Gbps, four optical 1 Gbps, per blade, plus four 4 Gbps or 8 Gbps Fibre Channel, with maximum of eight blades
Key features: 960 drive capacity; n+1 or n+m failover; multiprotocol SAN gateway; data deduplication; file-level retention; addresses Fibre Channel, SATA and flash drives

Hewlett-Packard (HP)
X1000 range (12 products)
Max capacity: 96 TB (Model X1800)
Max ports: Four 1 Gbps
Key features: Entry-level Windows Storage Server-powered unified storage with eight drive slots

Hitachi Data Systems
Hitachi NAS Platform 3000 Series (four products)
Max capacity (native): 4 PB
Max ports: Four 10 GbE; eight 1 GbE or two 10 Gbps; eight Fibre Channel
Key features: File tiering with WORM capability; single namespace across clusters up to eight nodes; thin provisioning; supports iSCSI, NFS and CIFS

IBM
System Storage N3000 Series (two products)
Max capacity (native): 104 TB
Max ports: 12 Fibre Channel, eight 1 Gbps
Key features: Entry-level NAS; supports iSCSI and CIFS; snapshots; data deduplication; RAID 6; custom OS; single-mailbox recovery

System Storage N6000 Series (six products)
Max capacity (native): 840 TB
Max ports: Eight Fibre Channel, four 1 GbE
Key features: Supports Fibre Channel over Ethernet (FCoE), iSCSI, NFS and CIFS; snapshots; data deduplication; RAID 6; 10 Gbps; custom OS; 64-bit architecture

System Storage N7000 Series (two products)
Max capacity (native): 1,176 TB
Max ports: 52 1 Gbps, 56 Fibre Channel
Key features: Manages non-native SANs; supports FCoE, iSCSI, NFS and CIFS; clustering; snapshots; data deduplication; RAID 6; 10 Gbps; custom OS

NetApp
FAS2000 series (three products)
Max capacity (native): 136 TB
Ports: Eight 8 Gbps Fibre Channel, eight 1 Gbps
Key features: Entry-level NAS; supports iSCSI and CIFS; snapshots; data deduplication; RAID 6; custom OS

FAS3100 series (three products)
Max capacity (native): 840 TB
Max ports: 40 Fibre Channel, 36 1 GbE
Key features: Supports FCoE, iSCSI, NFS and CIFS; snapshots; data deduplication; RAID 6; 10 Gbps; custom OS; 64-bit architecture

FAS6000 series (two products)
Max capacity (native): 1,176 TB
Max ports: 52 1 Gbps, 56 Fibre Channel
Key features: Manages non-native SANs; supports FCoE, iSCSI, NFS and CIFS; snapshots; data deduplication; RAID 6; 10 Gbps; custom OS

Reldata
Reldata 9240i Unified Storage System
Max capacity (native): 480 TB
Max ports: Six 1 GbE, two 10 GbE, two Fibre Channel, two SAS
Key features: Supports NFS, CIFS and iSCSI; replication; snapshots

Sun Microsystems
Sun Storage 7000 Unified Storage Systems series (four products)
Max capacity (native): 288 TB
Max ports: Two Fibre Channel, eight 1 GbE, two 10 GbE, InfiniBand
Key features: Up to 600 GB solid-state drives; data deduplication; replication; compression; snapshots; triple-parity RAID; supports iSCSI, NFS, CIFS and FTP

 

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This was first published in February 2010

 

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