The messaging platform can now cope with a million messages per hour – 100 times higher than its previous peak of 10,000
The GOV.UK Notify platform has been optimised to cope with a potential hundredfold increase in its usage.
GOV.UK Email recently switched its email notification system from a third-party provider to the Notify platform. This will require Notify to cope with sending an extra 500 million messages each year.
During the last 60 days of 2017, Notify sent a daily total of between 5,000 and 42,000 emails, at a mean of 18,000 per day. Extrapolated over an entire year, this average would equate to an annual total of just under 6.6 million messages.
Notify’s usage by the GOV.UK Email service requires the messaging platform to handle an average of about 1.5 million messages each day. It will need to be able to deal with a peak requirement of one million messages in an hour – a figure exactly 100 times greater than the 10,000 it was required to send in its busiest 60-minute period during the last two months of 2017.
- GOV.UK Notify goes live for central government, with local government to launch this year
- GDS updates Notify API
- GOV.UK Notify begins local government rollout
To prepare for this enormous increase in necessary capacity, the Government Digital Service tested Notify against three metrics. The first of these was the response time of the platform’s APIs. This equates to the length of time between a service provider sending a request to Notify and the email being placed in its queue for sending.
The second metric is throughput, which is the number of requests Notify can handle per second. The third is “round trip time”, which is the number of seconds between the platform receiving an initial notification request and it being able to confirm the successful sending of the message.
Testing discovered that Notify’s maximum throughput stood at 170 requests per second, less than half of the 360 requests it needed to be able to handle each second to meet the requirement of sending a million messages an hour.
Upgrades were made to Notify’s “high-availability database”, which now boasts 512GB of storage space, five times as much as it had before. It can support 10 times as many concurrent connections – a total of 5,000.
GDS has also adjusted the “throttling limits” of certain of its service users. GOV.UK Email has seen its limit raised to 24,000 requests per minute, compared with a default ceiling of 3,000.
Notify has also “upgraded [its] daily log size, to store additional logging information caused by increased traffic”.
“GOV.UK Email went live with the GOV.UK Notify platform on 7 March, and we are confident we can support an additional 500 million email deliveries per year and continue to scale,” GDS said. “We predict the number of daily messages sent through GOV.UK Notify will continue to increase month on month, as more services across the wider public sector start using Notify to meet their messaging needs.”