Monday, 24 January 2011

Data Storage Costs

The ADMIRAL project is creating a local data management facility and testing its use with researchers in the Zoology Department at Oxford University. The facility is built using a standard Linux operating system running in a VMWare hosting environment installed within the department.  The environment has a limited amount of local fast SCSI disk storage, but is also capable of using network storage via the iSCSI protocol.

One of the research groups for whom we deployed an ADMIRAL system started using it so enthusiastically that they rapidly filled up their allocated space, at which point they then stopped using the system without telling us.

With opportune timing, the Zoology Department has recently installed an iSCSI network storage array facility, to which disk storage capacity can be added on an as-needed basis. This facility is to be paid for on a cost recovery basis by projects that use it. We have performed tests to prove that we can use this facility within the ADMIRAL data management framework, and are now waiting for the Silk Group and IT Support to order and install the additional storage capacity so we can deploy an enlarged ADMIRAL server to meet the Silk Group's storage requirements.

We have also been in discussion with other research groups not currently involved with ADMIRAL about storage provision to meet funding body requirements for data sharing. Recently released BBSRC data sharing requirements ( stipulate that research data should be made available for sharing for at least 10 years beyond the life of a research project (i.e. a total of 12-14 years for a typical BSRC-funded project), and claims to allow the cost of this to be added to a research grant proposal to cover the costs thus incurred. See section "BBSRC Data Sharing Policy Statement " in their data sharing policy document. This does not require that data be kept online for this period, but considering cost, attrition rate and time to obsolescence of alternative solutions, some kind of online facility would appear to be as cost effective as any.

The cost of providing the departmental network storage facility has been estimated at about £400 per Terabyte over a 5 year period.  This is estimated on a hardware cost recovery basis, allowing for a normal rate of disk failures over the 5 year period, but not including departmental IT support personnel costs.  In discussions with our IT support team, we estimate that the project+10 year duration of required availability will approximately double the hardware-only cost of delivering on such a requirement. Based on these discussions, my current recommendation to Zoology department researchers bidding to meet these requirements would be to cost data preservation and sharing to meet BSRC requirements at £1000/Tb, assuming that departmental IT support remains committed to operational management of the storage server. I would also recommend that they allow 1 person day for each month of the project at appropriate FEC cost to cover data management support, especially if the research team itself does not have IT server systems expertise: I estimate this would reasonably cover ongoing support of an ADMIRAL-like system for a project.

For comparison, Oxford University Computing Service offers a 5 year data archive facility with multiple offsite tape backups for a Full Economic Cost of about £4000/Terabyte. They do not offer an archive service of longer duration. (It is important to distinguish here between a backup service and an archive service: the same OUCS facility provides a daily backup service, but said backups are destroyed after just a few months of no update or access.)

The university library service has tentatively indicated a slightly higher cost per Terabyte for perpetual storage.  The meaning of "perpetual" here is open to debate, but the intent is to maintain copies of the data in storage for at least several decades, much as historical books and papers are help by the Bodleian Library for the long term.

Friday, 21 January 2011

ADMIRAL Sprint 16

We have just completed our review of Sprint 16:
This was the first sprint in Phase 2 of the project.  For phase 2, our focus will be to consolidate and extend the ADMIRAL deployments with research groups, and to ensure that we can continue to support them and thereby gain greater understanding of local-level data management concerns through other projects to be conducted over the coming years.

Much of our effort in this sprint has ben focused on deployed system quality improvements that allow us to confidently roll out further ADMIRAL deployments, and in particular to separate configuration data from from the deployed system software so we can update the software without too much disruption to the ADMIRAL users.

Specific enhancements completed in this sprint include: 
  • Dataset repository submission tool usability enhancements
  • Improved deployment scripts to facilitate software updates
  • Improved test suite and generally improved system robustness
  • Tested ADMIRAL with a new departmental storage server
With these quality improvements mostly completed, our next immediate goal will be to extend the use of ADMIRAL by our research users.