# Front-end I/O metrics
<a name="frontend-io-metrics"></a>

The following metrics report cache-level information on system read and write operations. All these metrics take one dimension (`FileCacheId`) and are published into the `AWS/FSx` namespace in CloudWatch.


| Metric | Description | 
| --- | --- | 
| DataReadBytes |  The number of bytes for cache read operations. The `Sum` statistic is the total number of bytes associated with read operations during the period. The `Minimum` statistic is the minimum number of bytes associated with read operations on a single disk. The `Maximum` statistic is the maximum number of bytes associated with read operations on the disk. The `Average` statistic is the average number of bytes associated with read operations per disk. The `SampleCount` statistic is the number of disks. To calculate the average throughput (bytes per second) for a period, divide the `Sum` statistic by the number of seconds in the period. Units: [\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/fsx/latest/FileCacheGuide/frontend-io-metrics.html) Valid statistics: `Sum`, `Minimum`, `Maximum`, `Average`, `SampleCount`.  | 
| DataWriteBytes |  The number of bytes for cache write operations. The `Sum` statistic is the total number of bytes associated with write operations. The `Minimum` statistic is the minimum number of bytes associated with write operations on a single disk. The `Maximum` statistic is the maximum number of bytes associated with write operations on the disk. The `Average` statistic is the average number of bytes associated with write operations per disk. The `SampleCount` statistic is the number of disks. To calculate the average throughput (bytes per second) for a period, divide the `Sum` statistic by the number of seconds in the period. Units: [\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/fsx/latest/FileCacheGuide/frontend-io-metrics.html) Valid statistics: `Sum`, `Minimum`, `Maximum`, `Average`, `SampleCount`.  | 
| DataReadOperations |  The number of read operations. The `Sum` statistic is the total number of read operations. The `Minimum` statistic is the minimum number of read operations on a single disk. The `Maximum` statistic is the maximum number of read operations on the disk. The `Average` statistic is the average number of read operations per disk. The `SampleCount` statistic is the number of disks. To calculate the average number of read operations (operations per second) for a period, divide the `Sum` statistic by the number of seconds in the period. Units: [\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/fsx/latest/FileCacheGuide/frontend-io-metrics.html) Valid statistics: `Sum`, `Minimum`, `Maximum`, `Average`, `SampleCount`.  | 
| DataWriteOperations |  The number of write operations. The `Sum` statistic is the total number of write operations. The `Minimum` statistic is the minimum number of write operations on a single disk. The `Maximum` statistic is the maximum number write operations on the disk. The `Average` statistic is the average number of write operations per disk. The `SampleCount` statistic is the number of disks. To calculate the average number of write operations (operations per second) for a period, divide the `Sum` statistic by the number of seconds in the period. Units: [\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/fsx/latest/FileCacheGuide/frontend-io-metrics.html) Valid statistics: `Sum`, `Minimum`, `Maximum`, `Average`, `SampleCount`.  | 
| MetadataOperations |  The number of metadata operations. The `Sum` statistic is the count of metadata operations. The `Minimum` statistic is the minimum number of metadata operations per disk. The `Maximum` statistic is the maximum number of metadata operations per disk. The `Average` statistic is the average number of metadata operations per disk. The `SampleCount` statistic is the number of disks. To calculate the average number of metadata operations (operations per second) for a period, divide the `Sum` statistic by the number of seconds in the period. Units: [\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/fsx/latest/FileCacheGuide/frontend-io-metrics.html) Valid statistics: `Sum`, `Minimum`, `Maximum`, `Average`, `SampleCount`.  |