RDS gp3 disk geometry when expanding from 200 to 400 GB

0

Hello,

When we create a brand NEW RDS with gp3 storage of 400 GB, one can infer from RDS Enhanced Monitoring "Physical Devices Read" that 4 EBS volumes are created (which nets us 12,000 IOPS) with each gp3 provides 3,000 IOPS.

I am trying to figure out if it is the case if we extend EXISTING RDS gp3 volume from 200 GB to 400 GB - will we get 4 EBS volumes behind the scene? I tried to do test by creating RDS gp3 with 200 GB and then extend it to 400 GB. However, the extension process seems to break RDS Enhanced Monitoring, (see attached image where the physical device stats are now gone). With it gone, I could no longer infer how many EBS volumes were created behind the scenes.

Enter image description here

May we request:

  1. AWS clarifications of disk geometry when we EXPAND from 200 to 400 GB of gp3
  2. Investigate the issue of missing stats when we expand the gp3 disk from 200 to 400?

Thanks, Rob

  • Yes this is correct, RDS uses single volume for smaller allocated storage and RAID0 sets of 4 volumes for larger allocated storage. You can read more details about this here: https://aws.amazon.com/premiumsupport/knowledge-center/rds-stuck-modifying/

  • so this means that till 400 GB RDS uses a single gp3 volume and from 400 GB and above it uses 4 volumes. if so, when we are moving from let's say 350 GB to 400 GB, will the volume update take longer than usual? (as it's moving from single volume to 4 volumes)

Rob
asked a year ago390 views
1 Answer
0
Accepted Answer

Hello,

Providing update to my answer :-)

After waiting for a day or two, the physical device stats show up (in the enhanced monitoring tab).

At least in my test, when we EXTEND the existing 200 GB to 400 GB, RDS will change the geometry of the disk from using 1 EBS volume to 4 EBS volumes.

Enter image description here

Rob

Rob
answered a year ago

You are not logged in. Log in to post an answer.

A good answer clearly answers the question and provides constructive feedback and encourages professional growth in the question asker.

Guidelines for Answering Questions