Burst credit is the remaining throughput allowance for an Amazon EFS filesystem using Bursting Throughput mode. CloudWatch exposes it as the BurstCreditBalance metric. section 9.5.2
EFS accumulates credits while access stays below baseline throughput and consumes them during bursts. When the balance reaches zero, throughput decreases significantly. section 9.5.2
Operational limits include:
- EFS accrues 50 MiB per second per TiB of stored data. section 9.5.2
- The maximum balance is 2.1 TiB for filesystems smaller than 1 TiB and 2.1 TiB per TiB for larger filesystems. section 9.5.2
- A filesystem can burst for no more than 12 hours. section 9.5.2
Alerting on a low balance
Create an AWS/ EFS CloudWatch alarm for BurstCreditBalance, associate it with a FileSystemId dimension, and trigger it below a selected threshold. section 9.5.2
Table 9.2 EFS throughput depends on the storage size. (view table figure)
Compare filesystem size with baseline and bursting throughput to understand how quickly burst credit may be consumed. section 9.5.2
