AWS RDS 通用 SSD 或预置 IOPS

Question

Currently I have a RDS m4.2xlarge MySQL DB with 200GB of disk space allotted using general SSD, which gives me a limit of about 600 IOPS.

Looking at the monitoring I can see the most of the time the write IOPS are right at the 600 IOPS limit and can't go higher, then there are some short periods a lull followed by a burst over the 600 (I assume while my credits earned during the lull are burned). After the credits are used up it's back to the 600 limit.

My question is: is there are downside to running at the limit 99% of the time? My write queue depth is normally less than 2 and never really gets above 3.

Would I see any benefit buying provisioned IOPS (of say 1500) to handle the maximum peak requirements?

Currently I'm not really having any problems with the database, other than an occasional deadlock, but this seems to be expected for the amount of transactions going through the DB.

Answer 1

From the AWS documentation

Baseline I/O performance for General Purpose SSD storage is 3 IOPS for each GiB, with a minimum of 100 IOPS. This relationship means that larger volumes have better performance. For example, baseline performance for a 100-GiB volume is 300 IOPS. Baseline performance for a 1-TiB volume is 3,000 IOPS. And baseline performance for a 5.34-TiB volume is 16,000 IOPS.

In most cases the cheaper alternative is simply increase the disk space and get more IOPS allocated