Not quite a fair comparison because you are showing the price of a 1GB volume. However, if you had a 50 GB volume, then you would be paying $16.25 (50 * 0.325) per month on GCP, and you would be paying $9.25 ((50 * 0.125 + (30 * 0.10)) on Amazon for 30 IOPS.

I hope I have my math right here. Let me know if I missed something. If it's correct, then it seems like the bigger the volume that you have, the more sense it would make to go with Amazon.

Edit: I might have done the math wrong, it looks like Google gives you 30 IOPS per every GB you pay for, so a 50GB volume on GCP would actually be 1500 IOPS. If that's the case, then it's a very good offering from Google since you don't pay for disk access too!

Disclaimer: I work for Google as the product manager for Persistent Disk.

I suspect that what crb is referring to is the ratio of 30 IOPS/GB being the top ratio that could be bought and what that would cost on a per GB basis. I don't think crb was suggesting a 1 GB volume.

As for the specific case you describe - looking for 30 IOPS consistently on a 50 GB volume, with Google, there is no need to go to SSD for that or to pay $16.25/month.

- If you meant 30 random reads, you can hit that with 100GB of Standard PD for $4.00/month (with no IO charges)

- If you meant 30 random writes, it's less as 50 GB gets you 75 random write IOPS for $2.00/month (with no IO charges)

At Google, we've tried to bring consistency of performance even to the lower tier of block storage so no matter what level of IO you need, you can count on seeing a consistent level between volumes and over time.

So, how do you choose between the two PD types? As a very coarse rule of thumb:

- If you are looking for 2 random read IOPS / GB or less, growing Standard PD volumes to meet the IOPS needs is the most cost effective route

- If you are looking for 2-30 IOPS/GB, SSD Persistent Disk gets you the better value

(edit: "flat rate" = cost, not total flat rate. The 30 IOPS are per GB, so it scales with volume size. Sorry if I misled.)