Comment IBM has been announcing new storage products at a quickfire rate: SONAS, Virtual Disk System (VDS), and the XIV-based Smart Business Cloud are three of them. How do they fit together with each other and with the NetApp-sourced N Series and the DS3000/5000 and 8000 array offerings?
Steve Legg, IBM UK's chief technology officer for storage, starts from here; customers will want SAN (block access) or NAS (file access). For SAN: "Up to a cut-off point you'll want VDS. which includes the DS3000 and DS5000. Above this point it's XIV unless you need things like mainframe-attach or 3-site replication in which case it's the DS8000.
"XIV can reach up quite a long way and run parallel to the DS8000. For NAS there is the N Series up to around £250,000 and above that is SONAS."
This is a greenfield pitch. Customers with, for example, existing DS5000s, may prefer to stay with them and not embrace the VDS. Equally: "We don't expect to sell SONAS to people needing a smaller N Series product."
SONAS is the Scale-Out Network-Attached Storage product and it is highly scalable, having separated I/O controller and upper-level storage functions, which run in Interface Controllers, from the basic read and write storage functions which run in the Storage Pods.
The two flavours of hardware are connected by a 20Gbit/s InfiniBand switch from Voltaire. It means customers can add more Interface Controllers to ramp up the I/O capability and more Storage Pods to increase storage capacity.
Such a separation of scaling axes isn't possible with a storage design based on an integrated storage function stack running in a storage array controller, such as NetApp employs. But then, Legg thinks, NetApp doesn't expect to be pushing its offering up to the multi-petabyte level where SONAS plays.
SONAS employs drive enclosures packing 90 drives into a drawer with access from the top. These come from DataDirect. Legg says IBM was supplying the DataDirect drive enclosures already in certain specific customer use cases, and was familiar with the box and its drive packing density. DataDirect also uses IBM's GPFS (General Parallel File System) in its Gridscaler product, so there is a good relationship here. The choice of these enclosures, Legg says, "was all about density".
The Smart Business Cloud was a precursor of SONAS. Legg says SONAS doesn't replace the Smart Business Cloud as it has specific cloud-related functionality that SONAS does not. In fact SONAS could be the storage delivery part of the Smart Business Cloud now.
In passing, IBM has no plans to change the RAID 1 mirroring scheme inside XIV, part of its value being its simplicity. If a different RAID scheme is used, "we just drive up the complexity".
The Scale-Out File System (SOFS) was also a precursor of SONAS, but its components were delivered as part of a service engagement whereas SONAS is a product, productised SOFS in a way.
SONAS customers are ones needing an alternative to dozens of NAS filer islands, ones with thousands of files or a large number of large files: "which is the happy hunting ground of GPFS anyway". They'll typically be in the university, pharmaceutical and media environments and there is an overlap with HPC (High Performance Computing), with the GPFS part of SONAS being capable of delivering an enormous amount of bandwidth out of the box.
VDS, currently a UK offering, is being rolled out worldwide. It packages IBM's SAN Volume Controller (SVC) with either a DS3000 or DS5000 array, and Tivoli Productivity Center manager software, and is a packaged product set for IBM's channel.
Legg says: "It's very much a channel play and they like it. It's an offering that can go head-to-head with Dell/EqualLogic and [EMC CLARiiON] CX4, and have superior functionality and pricing."
HP LeftHand, now P4000, products are also in VDS' sights. As there is a centre of SVC expertise in IBM Hursley the UK part of IBM seized upon VDS and is running with it first.
Because VDS contains an SVC product it can virtualise third-party arrays as well as the included DS3000 and DS5000, with around 114 third-party array controllers being supported.
IBM is keen on the idea of separating persistent read/write basic storage array functionality from upper level storage functionality like virtualisation. Legg admits that there is less optimisation possible as there is with integrated vertical stacks, such as NetApp's, but says it's much easier to add functionality and to scale with such separated layers.
So that's it; that's how IBM's storage offering is simplified: VDS, then XIV and DS8000 for SAN access, and N Series followed by SONAS for file access, with the Smart Business Cloud being used where specific cloud plumbing is needed - Big Blue's storage strategy in a nutshell. ®