SAN charges
Both SAN services are charged services to cover the capital cost of purchase, replacement and maintenance.
The charges over a 5 year period are the same in both SANs for SATA storage and tape backup but are charged in different ways to reflect the different ways that the SANs are funded.
High performance Fibre Channel (FC) attached disks are available on the Infrastructure SAN for a premium.
Disk charges
Disk storage is charged per terabyte of the raw disk sizes. After removing the overheads for resilience (RAID) and formatting this results in the visible storage available for data being approximately 0.78 of the raw size.
Disk charges are quoted per raw terabyte, but storage is available in units of 250GB. i.e. 0.25TB, 0.5TB, 0.75TB, 1TB etc. and is charged pro-rata. All charges include VAT and are reviewed annually.
Backup charges
A single tape backup facility covers both the Infrastructure SAN and the ECDF SAN. The only differences being the charging model which reflects the way funds have been obtained for the facility.
The charges are the same when calculated over a 5 year period. The charges are per terabyte of actual data (which equates to about 0.78 of the raw disk storage) to be backed up.
Backups are based on the concept of a weekly "backup cycle" each of which comprise one full backup and six incremental backups.
Choosing more than one backup cycle will lengthen the amount of time that data is retained before the tapes are overwritten e.g. 3 weeks retention of data on tape requires 3 backup cycles.
The charges are quoted per terabyte per backup cycle. So if you want 2TB of data backed up and retained for 3 weeks, the charge would be (2TB data x 3 cycles) = 6 times the 1TB cost above.
Note
Where data changes very little, a backup cycle of seven weeks rather than seven days may be more appropriate.
This would comprise one full backup and six incremental backups at weekly rather than daily intervals. This would need to be discussed with the service provider and will be determined by the nature of your data and its usage.
Connection costs
There may be an additional cost to connect a new server to the SAN storage or backup facilities. These costs may include relocation of the server, purchase of Host Bus Adapter cards, ports on the SAN network and backup licences.
Infrastructure SAN cost calculator
This handy calculator can be used to estimate the cost of providing file and backup services via the different tiers of storage available on the Infrastructure SAN.
This article was published on Nov 28, 2012