DoC Computing Support Group

DoC Private Cloud: NetApp Scalable NAS Storage

Peter Pietzuch recommended that we also investigate commercial scalable storage systems - specifically NetApp "scalable NAS" units - which his colleagues at the University of Cambridge Computing Laboratory have used for years. CSG have discussed NetApps with colleagues in ICT and Martyn Johnson at the Cambridge Computing Lab, and have now managed to get a realistic quote from one of our main suppliers, Q Associates, discussed below.

CSG would like to point out that NetApps are an entirely unfamiliar technology to them, in contrast to commodity storage options, and despite various positive discussions with people who are more familiar with them, there is a significant risk of buying a NetApp effectively sight unseen. All our storage eggs would definitely be in the one basket!

What are they?

NetApp make a range of scalable Network Attached Storage systems, essentially lots of disk shelves (aka "Just a Bunch Of Disks == JBOD), with a high degree of fault tolerance. In particular, each NetApp comes with a dual-head pair of controllers, each of which can take over the other's function if one dies. Both controllers are attached to all the disk shelves via independent data paths. The controllers run NetApp specific storage management software called Data OnTap - common across the whole range of NetApp storage systems. A NetApp running Data On Tap can create volumes across sets of disks (using various RAID levels), export those volumes as conventional POSIX filesystems via NFS and CIFS (Samba/SMB/CIFS is the Microsoft file serving software), and also export raw block device volumes via iSCSI or via physical Fibre Channel connections to hosts.

Data On Tap provides many clever software features, such as data deduplication and very cheap snapshotting, and can even replicate chosen volumes, asynchronously or synchronously, to a second NetApp if desired. However, software features are licensed individually or in bundles, so you might have a NetApp but be unable to use certain features without spending more money on licenses.. You also choose how much money to spend on support (there are various different options to choose from). NetApp pride themselves on the reliability, performance and support side of the equation.

What Models are there?

The main models are the entry-level FAS2240-2, FAS2240-4 (a 4 rack unit high version) and FAS3240. Bigger models exist (eg the FAS6240) if you have megabucks. ICT have recently purchased an IBM rebadged FAS3240 (reusing their existing fibre channel connected disk shelves) to replace or augment their SAN.


CSG have spent a lot of time trying to get ballpark estimates of NetApp FAS2240 or 3240 prices. We've had useful conversations with various ICT people about NetApps, reliability, support and performance, but have not managed to discover a price and an exact spec of the IBM rebadged NetApp they purchased. We've spoken at length with two NetApp parter organisations, have had lots of sensible discussions about them trying to understand what we want to do, how much I/O load we'd put on the storage system - unfortunately impossible to even estimate! - but it took over a month to get an actual sensible price from one of them - Q Associates.

All prices quoted below exclude VAT.





Entry level FAS2240-2 High availability (dual controller) system with a single disk shelf of 24x600GB disks



fast Fibrechannel drives, 10K RPM

Additional disk shelf of 24x2TB drives



slower SATA drives, 7.2K RPM

Software licenses for the above




3 yr support




for a grand total of £50,400 + VAT, for approx 12TB of fast usuable diskspace plus 40TB of slower usuable diskspace.

At this price, we probably couldn't afford two of them. Note also that for that price, we could buy Dell commodity storage servers giving approx 140TB of usuable diskspace (all SATA based, i.e. the "slower" option), or even 200TB of usuable diskspace using a different Dell server variant with 12 x 2TB drives for £1,200 less than the 24 x 1TB drives main option..


project/privatecloud/hardware/netapp-storage (last edited 2012-05-15 15:04:05 by dcw)