Derbyshire County Council has implemented a tiered storage architecture by adding a NetApp NAS tier to its existing HP EVA SANs and has saved £200,000 of expected storage costs over the next two years by freeing up capacity.
The council has 8,000 IT users and supplies IT services across more than 400 sites from two main datacentres; a primary site in Derby and a secondary site 20 miles away at Darley Dale that are connected by a 10Gbps link.
Derbyshire council originally consolidated from direct-attached storage on servers to an HP SAN in 2003 as the organisation moved to a central IT model.
By 2012 the two HP EVA 8400s held 250TB across the two sites on high I/O performance fibre channel drives. All data – structured and unstructured – was lumped in together with a pair of file servers acting as file access gateways for shares of files held on the EVA SANs.
The situation posed a number of key problems for datacentre manager Rob Skermer. Namely, the EVA SAN was likely to soon run out of capacity, all data was held on the most expensive high IOPS drive type, and the IT team could not use functions such as replication or data deduplication for file data accessed via the file servers.
“If we continued to get the same level of data growth we’d have soon run out of capacity and we wanted to release some capital and gain the benefits of, for example, data deduplication,” said Skermer.
Derbyshire County Council evaluated a number of NAS products to which it could migrate file data to created a tired storage infrastructure and eventually settled on NetApp, which it implemented with the help of Northampton-based integrator Phoenix.
With Phoenix, Skermer’s team moved file data off the HP EVA SAN to a pair of mirrored NetApp FAS2240s with Sata drives that now hold 40TB at each site.
The move created a tiered storage architecture in which business critical structured data and virtual machine files have been kept on the HP SANs, but unstructured file data formerly held on the EVAs has been moved to the NetApp filers.
The project has resulted in data being better matched to the media it is held on, with rapid access structured data such as databases being held on the block-access tier one HP SAN while unstructured file data is retained on the NetApp boxes that form a NAS tier two.
Derbyshire council can now also take advantage of advanced storage functions for the file data on the NetApp FAS2240s, such as data deduplication that has resulted in a 2:1 data reduction ratio, asynchronous SnapMirror replication plus failover between the two sites.
Data protection of file data has also been made much more efficient by use of replication. Where previously agent-based LAN backup to LTO-4 tape took almost a whole weekend data is now mirrored in near real time. Restores are now almost instantaneous too as data is held for around 30 days on disk with no tape infrastructure to negotiate.
Overall, Skermer calculates the creation of the tiered architecture has saved around £200,000 in storage outlay over the next three years.
He said: “The total cost of the solution was £112,000 and we expected to spend about £100,000 a year for the next three years of storage, which we won’t have to do now because of the capacity we have freed up on the SANs.”