Wednesday, 25 July 2012

What is a servers economical life

In some industries they see it as important that a computer hardware has a long lifespan.  I hear that in the oil industry they are looking to get 7 years out of their servers.  Is this realistic.  In my opinion no.  Anybody that expects the highest possible uptime should not expect more than 3years, at most 4years,  lifespan from a server, or other computer hardware with moving parts. 
There is a reason for that with most manufacturers the 3 year warranty is cheap, year 4 reasonable and the cost of year 5 can be accepted.  Any more than that and there is definitely no economy in it.  It’s cheaper to buy new.  The trouble is in most cases no1 the harddisks and no2 the power supplies.  No amount of guarantees can make them live longer.  All the guarantees do is ensure there is something there to swap them with when they do fail, and failure usually mean some sort of downtime. 
A problem is that no hardware manufacturer will give you a “guarantee to fix”.  Service contracts involve a guarantee to maximum time before engineer is on site, and often a second maximum time until part is on site.  In the old days these where one and the same since the service engineer had a ll the most common parts in the back of his car.  These days stock is smaller and the part might be a flight away.  Not good if your problems is during a volcanic ash crisis, or a 9/11.
I can see the attraction of 7 years if you are in the sample financial industry since there is requirements to keep financial data for 7 years.  It is however better to prepare a migration path early, because it will be needed. 
Another requirement when trying to extend the life of hardware is frequent monitoring.  And here I must insist on the necessity for physical presence in the computer room.  Those blinking lights will for the trained eye give early warning.  They are also much easier to see than a line of log hidden among thousands.  Today we see the opposite trend with many being proud of their dark data centres.  Dark here meaning no light due to no manpower on site.
The necessity to be prepared will increase as more and more backups are online or on secondary storage.  They will expire just as fast as other hardware.  In the old days tapes could last long if they where kept well and tested for failure at regular intervals.  Always keep 2 at least copies because tapes did have a high failure rate due to stretch.  To ensure recovery I always brought 3 sets to the dr centre.  One problem is to find something to restore them on when they are needed after several years. 
A diskdrive is a diskdrive and they will fail eventually due to that they have moving parts inside.   A possible solution can be the ssd that could be written to once and then , which would help against its so and so many writes sudden death syndrome.  Currently however due to its cost its not taken up in any large numbers. 
Ssd’s  is not a solution for the parts of servers/applications/databases that requires frequent rewrites.  It could even shorten the lifespan of the hardware requiring a higher rate of turnover.  There have in use for high turnover database logs been reports of whole shelves of ssd’s failing at once, after less than 2 years of service.

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