Saturday, November 16, 2019

Story of reducing EBS volume size

As my previous writing stated, technologists journey is filled up by unexpected challenges at unexpected places due to unexpected reasons.

Motivation

AWS offers Elastic Block Storage (EBS) as hard drives for EC2 instances.  One of our EC2 instance used a 40GB EBS volume which cost us about $4 per month, but we are only using 5.5GB of that 40GB, so I have been thinking of reducing size of storage to save cost, however, unlike the convenience AWS gives you when expanding storage size, it is totally a different animal if you try to reduce EC2 storage size. $4 a month is not big deal, but given prospect of our rapid growth in future, despite the technical challenge and unavailability of its know-how, I felt it's necessary to take on this challenge and solve it.

Fire: Following Wrong Tutorials

As one of the tutorial mentioned, It turned out to be a 6* hour gruesome effort luckily with a happy ending.  But before the happy ending, like the theme of this blog, this effort of exploration started a fire as I followed these steps:

  • google search keyword "reduce EBS volume size"
  • following steps of 2 tutorials at top of Google search results but failed after about 4 hours of effort


Fire Drill: Find and Follow Correct Tutorials

Now after spending the previous 4 hours walking the wrong path, I recollected the reason for failure being the fact that EBS volume I tried to shrink size being system boot drive, while the tutorials I followed did not address this particular characteristic, therefore I adjusted google search term and did the following

  • googled again by adding some keyword related to boot or startup and found another tutorial which looks better than previous two
  • following the tutorial and achieved goal


Lesson Learned

For a technical issue with multiple online tutorials each offer a different solution, Google's ranking of search results (these online tutorials) is not a reliable metric to measure quality and reliability of these tutorials. 

If you run into similar problems or would like to learn more details of this story, please contact buytition@gmail.com

No comments:

Post a Comment