We had been in the old datacenter for six years or more, hosting some of the servers which are of the same age.   In fact when we migrate, there are some servers that hasn’t been down for 1000 days or more.   Migrating such servers especially with old hardware is quite tricky and requires special care.

Also a lot of the servers that we are hosting aren’t actually from Singapore, they can be as far away as Europe or USA.  Synchronizing the migration with them is another challenge.

What we had done is to stop adding new servers about 6 months before the actual migration.   Having trunking with the old and new datacenter means that we can just unplug any server, bring to the new datacenter and plug it in and it will work without changing any configuration.

With the trunking and all precautions in place, we set to migrate the servers in 6 weeks.  We do not do everything in one shot as we need to cater to clients who requires different downtimes and different dates as they are running certain processes or campaigns at the particular date.   A six week migration plan allows us to cater to our clients requirements and to minimize the clients’ inconvenience.

Migration was in batches and despite the best of precautions, some old servers failed and our technicians need to rescue them.   The 6 weeks time allowance cater to failures and the time needed to rescue the failed servers.

Migration was completed on the last day, the 30 Nov 08.   Even after this, we do not consider the migration completed until we have observed all servers and take the opportunity to change the power supplies or CPU fans of some of the servers.   I guess the cost to us for the migration easily exceed 5 figures but this is necessary to avoid inconvenience to clients and to assure maximum uptime.

Overall it wasn’t an easy job, hopefully we can start at this datacenter for the next 6 years or more.   Migration is kinda a 4 letter word for web hosting providers like us.