Re: Increased read IO wait times after Bullseye upgrade
On Tue 8 Nov 2022, at 09:48, Vukovics Mihály <vm@informatik.hu> wrote:
> Hello Community,
>
> since I have upgraded my debian 10 to 11, the read IO wait time of all
> disks have been increased dramatically.
[...]
> Chart attached, you can clearly see the date of the upgrade.
>
> Any ideas?
Hello,
I'm not an expert in the area, but a few thoughts:
---
(Seemingly unlikely issues)
Hardware problems coincident with upgrade - smartmon tests?
Fragmentation? What % capacity is used? What filesystem?
---
RAID status?
Have you rebooted?
After a quick web search, this article suggests iowait may not be the best indicator of problems (though not sure if this extends to wait times for particular operations)...
https://ioflood.com/blog/2021/01/25/iowait-in-linux-is-iowait-too-high/
...does iostat's %util give cause for concern? (per the article)
HDDs or SSDs? The article suggests ~100ms may be reasonble for HDDs - your chart only seems to show one outstandingly high wait time - do you actually notice a difference in performance?
Not sure if any of that helps but I will follow the thread with interest.
Nice chart btw. What produced the data and the chart itself?
Best wishes,
Gareth
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