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When sql server choose the I/O size for a single read/write (Data file random IO)?
8KB
64KB
or even larger
" Different SQL Server operations will be different of reads and writes."
any official MSDN doc for this ?
I still can't see any official taking about that
Hi @sakuraime ,
Although we can not find the exact words or sentence in MSDN doc. , we can conclude and test it.
Main operations as next:
You can search these operations in google and then verify those.
If this reply is helpful, please do "Accept Answer".
BR,
Mia
This link has official downloadable white paper. I quote from the white paper
Readahead pages/sec Pages reads/sec measures the number of physical page reads being issued per second.
Read-ahead pages/sec measures the number of physical page reads that are performed using the SQL Server read-ahead mechanism. Read-ahead operations are used by SQL Server for scan activity (which is common for data warehouse and decision support workloads). These can vary in size in any multiple of 8 KB, from 8 KB through 512 KB. This counter is a subset of Pages reads/sec and can be useful in determining how much I/O is generated by scans as opposed to seeks in mixed workload environments.
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When sql server choose the I/O size for a single read/write (Data file random IO)?
8KB
64KB
You should work with your system or storage administrator, and depending on the type of system.. do they we still the term OLAP and OLTP ? If it's a highly transactional system you can actually design your storage to optimize for certain block sizes (smaller), where as for reporting and ETL systems you could optimize for throughput reads..so you can larger chunks (larger block sizes) defined for storage. You can do some research to help verify that, but that's my experience/research before and recall from optimizing storage related to dbs. Random IO definitely smaller sizes for defining your storage sub system.