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I understand reboots are necessary, but why not migrate the instances from a node to a different node, reboot the node now that there are no instances running o
by X-Istence 12y ago
I understand reboots are necessary, but why not migrate the instances from a node to a different node, reboot the node now that there are no instances running on it, and do this in a rolling manner?
- taf2 12y agoBecause it's unknown which servers and when - they are bouncing physical servers... We avoided any major downtime by being multiple dc's
- X-Istence 12y agoI understand that Rackspace is rebooting physical servers. They also have the knowledge to know what VM's are running on said machines, and they also have the ability to migrate the VM's from one compute node to another compute node.
- harlowja 12y agoIf they have network block storage you would likely be correct, but afaik they also give you emphemeral storage that is local to the hypervisor which is not network block storage and therefore makes it very very hard and very very slow to migrate you around automatically (ever tried transferring a 20GB+ file around, ya, it takes forever...)
- X-Istence 12y ago20 GB file over 10 Gbit/sec would take 16 seconds. I just recently migrated a 180 GB instance from one KVM compute node to another in 3 minutes.
- regularfry 12y agoDepending on the nature of the patch, they might not be able to migrate from unpatched to patched hosts. KVM upgrades can also be fun that way.
- ownagefool 12y agoThe VMs are _probably using local disk storage, thus live migrations would be non-trivial to achieve and may be impossible given their current setup. From memory[1], you had to be migrating between the same architecture, and if they're anything like the smaller providers they're running less bigger nodes, and thus it's actually a lot quicker to just push the power button. [1] I worked with Xen years ago, my information is no doubt out of date.