[olug] PayPal outage

[David Walker]

Every decent system, Windows or Linux or anything else, can be rolled back.  
This isn't a function of the operating system but rather the developers.

cvs is an open source system that runs on Linux or Windows and can handle this 
sort of thing.  Another alternative for rollback functionality can be 
achieved simply by copying changes from development to live into a directory 
pattern like (c:)/web/mysite20041014/ and then changing the active web site 
directory to that one either by changing a symlink or changing the web site 
configuration.

But, PayPal handles financial transactions which means that any changes to 
database structure could be hard to undo.  Say they change something in the 
database and then process 1500 transactions before discovering a glaring bug.  
They have a responsibility to preserve those 1500 transactions meaning that 
if they reverted to the database version prior to the upgrade (and their 
database is most likely monstrous) they would have to re-enter the 1500 or 
whatever transactions into the old database before they could allow new 
transactions.

Any serious changes like this, on a site as large as paypal, would need to be 
tested and retested and a reversal plan may have to be designed and even some 
software written to implement in case of reversal.  It can be hard to get 
those time and financial costs justified as the leadership often wants the 
features quickly and cheaply.



On Wednesday 13 October 2004 09:10 pm, William Haisch wrote:
> Just wait:  in a month, all the trade rags will say Windows rules and
> Linux is not enterprise ready because of this outage at PayPal.  So
> this begs the question:  When running Linux and Apache in an enterprise
> environment, is it true that changes on Linux can't be rolled back or
> reversed?  Is this a matter of planning and setup or a true limitation
> of the platform?  Does this mean that PayPal doesn't know what its
> doing?  Should I trust them with my money?