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What are useful rule-of-thumbs with regard to interpreting non-zero vmstat "bi/bo" values? When are the values "okay" and when are they an indication of that the system is under heavy stress?

The question is of course hard to answer in the general case, but I'm looking for rule of thumbs rather than exact rules.

knorv
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2 Answers2

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It's probably a lot better to run "iostat -x" which will often give a percentage utilization of disk I/O bandwidth for each device.

If you don't have iostat, then I'd run "hdparm -t /dev/sda " in a loop for a while while running vmstat in another window to give you a baseline for what a lot of I/O looks like.

Michael Mittelstadt
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  • Agreed; % utilisation is often far more useful, and it's surprising how few MB/s a busy (traditional hard) disk can sustain under random workloads and/or high I/O queue lengths. Also, `iotop` or htop's I/O tab are great for identifying the main culprit processes. – screwtop Jan 12 '23 at 22:42
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bi and bo represent the data transfers between virtual memory and block devices. It depends on your workload. No rule of thumb exists.

0x44
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