EC2 instance very slow after EBS volume resize

Question

I have an instance on EC2 that is a t2.medium and it was with a 75GB gp2 hard drive( which is a general purpose SSD). After change to a 110GB gp2 hard drive the whole machine is really slow..

My python script used to take something like 40 to 60 seconds to uncompressed some zip file and now its taking 3 to 5 minutes.. If multithreading of this script is running it takes for ever..

Any idea of that happened or how to solve it?

Windows running there..

Answer 1

When you "resized" the disk volume what you really did was create a new larger EBS volume from a snapshot of the old volume. The new EBS volume becomes available immediately but you have to go through an "initialization" process to get it to load all the data. The first time you access a particular block of data on the new volume it will be slow. Subsequent attempts to access that block of data will occur at the fast speed that you would expect. You can read more about this here .