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sysstat / sysstat

Performance monitoring tools for Linux
https://sysstat.github.io/
GNU General Public License v2.0
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Feature Request: Add disk read and write wait times for disk collection data #364

Open MrPippin66 opened 1 year ago

MrPippin66 commented 1 year ago

Frequently, we'll see issues that are specific to differences in write times vs read times, and 'sar' data only provides a cumulative time for both read and write.

Linux and other OSes provide the read and write response times in addition to the cumulative times.

It would very beneficial if 'sar' data included this data as well.

I don't show any pending feature request of the same kind from what I could fine.

In the specific case of Linux, the data is provided in /proc/diskstats as:

Column Description 7 time spent reading (ms) 11 time spent writing (ms)

MrPippin66 commented 1 year ago

Is this under review?

sysstat commented 1 year ago

Hi, I have no plan to add this feature to sar for now. iostat already makes this distinction between read and write times.

MrPippin66 commented 1 year ago

I understand that "iostat" provides this. The issue is this distinction in missing in the historical data for 'sar', which makes diagnosing issues that occured in the past difficult that need this distinction.

In enterprise environments, the difference between read and write performance can vary significantly. The average of the two that 'sar' provides hides this from historical examination.