The British Transport Police (BTP) protects more than six million passengers a day as they travel on the UK's railways.
The body relies heavily on information generated by specialist Command Control, Crime Reporting and Intelligence applications to carry out its operations effectively.
But until recently, BTP's assistant technology manager for infrastructure, Philip Clifton, had a problem: how to provide the force with access to the growing volume of data those applications store at up to 148 sites across the country while cutting down on the associated management costs and simultaneously beefing up data security and disaster recovery processes.
The solution was twofold: first, it saw a server virtualisation project that replaced the ageing physical servers and legacy direct attached storage (DAS) arrays that made up the bulk of the BTP's distributed architecture, much of which was reaching capacity and was difficult to upgrade or scale out further.
Second, saw the installation of two storage area networks (SANs) based on Dell Compellent's Fluid Data hardware and software platform at the BTP's Camden datacentre. This replaced HP enterprise virtual array (EVA) and StorageWorks MSA Fibre Channel and iSCSI equipment with arrays that accommodate a mixture of Fibre Channel, SAS and solid state disk (SSD) drives to support storage tiering, whereby data is automatically migrated to less expensive media according to pre-defined rules around data retention or access policies.
"We had massive server sprawl of about 230-odd servers across the estate, all purchased as point solutions for specific applications and now virtualised down to about 140 VMs that have gone onto four physical servers"
"All the stuff will be redeployed or scrapped - we had massive server sprawl of about 230-odd servers across the estate, all purchased as point solutions for specific applications and now virtualised down to about 140 VMs that have gone onto four physical servers," says Clifton.
"Some of the storage hardware is a bit long in the tooth – EVAs and MSAs for example – and we will not redeploy those, though the EVAs may have use in specific areas like third tier backup."
The BTP originally purchased around 25TB of disk capacity to accommodate the data migrated onto the Camden datacentre from the outlying sites, but Clifton quickly realised that was not enough and topped it up with another 15TB to handle additional information found in various structured and unstructured databases, including standard Office documents like Word, PowerPoint and Excel.
"There were probably 20 to 30 sites that had either data repositories or applications we did not know about – we had very little control on backups or how data was managed," says Clifton.
"Now we are bringing all the data back from those sites via RoboCopy [Windows Server 2008 Robust File Copy command-line directly replication] for clarification – to make sure that the data being copied is up to date – then we can target a switch-off of the original source and repoint people's applications [to the centralised repository]."
The SANs use integrated replication and snapshotting software for backups, and data de-duplication software to eliminate multiple copies of the same information to reduce the backup size and minimise storage capacity requirements, for which Clifton estimates a compression ratio of 30-40 per cent.
The BTP estimates the capital cost of the project – £400,000 to £500,000 – could be repaid within at little as nine months, if anticipated savings in power, management and future upgrade costs are realised.
The Fluid Data architecture migrates data to lower cost SATA drives depending on how often the information is accessed, with 95 per cent of the data already moved off more expensive Fibre Channel and iSCSI disks.
"Those are the procurement costs, which were a good 30-40 per cent cheaper than what the competition quoted," says Clifton. "We did a like-for-like run against HP and Compellent came on top, especially as we had Dell servers and it fits well with our existing storage and virtualisation environment."
The BTP was fortunate in having prepared the ground for the storage upgrade already, having updated its servers as part of the virtualisation project. A "pretty comprehensive" scaling and scoping exercise had also specified a network upgrade before the end of the current year, which will support a planned BTP migration to voice over IP (VoIP).
"Our two primary sites have fully redundant Gigabit Ethernet WAN interfaces and we have others with 100Mbit/s ports," says Clifton. "We have some at 60Mbit/s with WAN optimisation, as well as 256Kbit/s leased lines on a very old contract."