Dayalan T •,
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As I understand, you want to know the root cause of the IO request increase in Azure SQL Managed Instance.
Please let us know if your ask is different.
In the General Purpose service tier, every database file gets dedicated IOPS and throughput that depend on the file size. Larger files get more IOPS and throughput. IO characteristics of database files are shown in the following table:
|IOPS per file||500||2300||5000||7500||7500||7500|
|Throughput per file||100 MiB/s||150 MiB/s||200 MiB/s||250 MiB/s||250 MiB/s||250 MiB/s|
If you notice high IO latency on some database file or you see that IOPS/throughput is reaching the limit, you might improve performance by increasing the file size.
There is also an instance-level limit on the max log write throughput (see the previous table for values, for example 22 MiB/s), so you may not be able to reach the max file throughout on the log file because you are hitting the instance throughput limit.
Hope this helps.
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