A couple years ago I posted articles inquiring as to the state of OpenVMS and PI System dependencies on OpenVMS within our PI System user community. Now that a couple of years or so have passed - just the other day I was thinking about this again. There still remain a number of PI systems, mostly PI3 servers, which depend on interface nodes or application nodes running OpenVMS. A goodly number of these OpenVMS systems, based on VAX and Alpha platforms, are considered mission or business critical.
Just how long can we expect this stuff to run that we type on and archive PI data with? Let's think about just the disk drives for a moment…
Disk drives for ”modern” OpenVMS systems had advertised very long lifetimes and smart hardware. Disk drives in OpenVMS systems which were new in the late 1990’s and early 2000’s were pretty capable and included advanced features helping to implement RAID and caching implementations in drive hardware as compared to other computing systems of the same era which may have implemented such features in disk controllers, or microcode in processor boards, or in operating system disk device drivers.
A typical Wide SCSI drive from this era might have advertised 800000 hours MTBF (nearly 100 years!), however… That was a hugely big "However": MTBF was affected by handling, storage, power up method (and power fail), error rate and so on.
- Nearly 20% of storage capacity of such drives was reserved for system/hardware functions such as engineering partition, dedicated head landing zone, sectors reserved for error replacement, and auto calibration/head alignment functions.
- These disks anticipated an average of as many as 100 sectors failing per year of operation.
- The way DC power was applied to the drive and the manner of application of the first SCSI controller commands after power up affected drive life and lifecycle.
As a consequence of these features, disk life was expected to be only 5 years in normal use. Here at OSIsoft we are experiencing average lifetime of these disks to range from 5-8 years.
Similarly limited lifetimes apply to our OpenVMS server's disk controllers, memory boards, processor boards and so on. The last VAX/VMS system was built September and shipped in December of 2000.
And we know the last Alpha OpenVMS system was ordered in April 2007 and shipped later that year. We can expect nearly all VAX and Alpha based OpenVMS systems to be past end of life at this point in time.
Seagate Barracuda ST15150N specification sheet and reference manual