Viewing I/O Statistics for ZFS Storage Pools
To request I/O statistics for a pool or specific virtual devices, use the zpool iostat command. Similar to the iostat command, this command can display a static snapshot of all I/O activity, as well as updated statistics for every specified interval. The following statistics are reported:
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alloc capacity -
The amount of data currently stored in the pool or device. This amount differs from the amount of disk space available to actual file systems by a small margin due to internal implementation details.
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free capacity -
The amount of disk space available in the pool or device. Like the
usedstatistic, this amount differs from the amount of disk space available to datasets by a small margin. -
read operations -
The number of read I/O operations sent to the pool or device, including metadata requests.
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write operations -
The number of write I/O operations sent to the pool or device.
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read bandwidth -
The bandwidth of all read operations (including metadata), expressed as units per second.
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write bandwidth -
The bandwidth of all write operations, expressed as units per second.