A survey conducted on cloud users following the Xen vulnerability discovery that forced Amazon Web Services, Rackspace, and Softlayer to reboot their instances has found that AWS users had the least amount of downtime.
The Xen vulnerability was discovered on October 1st, and the three cloud providers had to reboot many of their cloud instances in the following week.
The survey by Rightscale fetched responses from 349 AWS users, 66 Rackspace users, and 42 SoftLayer Virtual Server users. The rest of the numbers are made up by respondents who use multiple clouds.
The reboot caused some concern in users who were worried about how it would their applications. Amazon Web Services came out on top with 51% of its users reporting no application downtime during the reboot, with a further 21% reporting less than five minutes of downtime.
When it came to Rackspace, 27% of its users reported no downtime, and 26% of users experienced no outages with SoftLayer.
Another way to measure how the three providers fared during the reboot is measuring the most amount of downtime users experienced.
To that end, 5% of AWS users reported more than an hour of downtime, compared to 13% for Rackspace and 17% for SoftLayer.
On the other end of the spectrum, the percentage of users of each cloud that reported more than an hour of application downtime was 5 percent for AWS, 13 percent for Rackspace, and 17 percent for SoftLayer.
However, the results were likely impacted by the fact that AWS did not have to reboot all instance types, further helped by AWS users having the ability to relaunch instances ahead of the reboot and move resources to unaffected instance types. A number of AWS users were also employing multiple availability zones.