Hi,
I'm suffering performance issue with my disks.
its for a datawarehouse, so I setup the SQL Server flag to use the extended pages. its supposed to read 256Kb instead of 64kb.
on my tempdb drive, the average disk bytes/transfer is around 512Kb. which appear to be correct. its a constant value during my process
but my database itself, I see random values between 8kb to 193kb. which results in bad performance. I got only 40 to 80Mb/sec here compared to 450MB/sec for the tempdb...
I expect to see a constant 256kb here or 512kb with read-ahead requests, but its not the case.
my table is compressed, is it the reason why SQL Server don't read 256kb?
my table is store in a file group with 1 file only (I have other tables in other FG). the tempdb is setup with 4 files (but I don't saw noticeable changes between 1 file and 4 files here)
the windows volume was formatted at 64kb for the database (the tempdb drive was incorrectly set to 4kb, I have to solve this)
when I run benchmarks using sqlio, the avg bytes read / transfer match the size set in the test.
so I'm looking for some guides here to explain why SQL Server don't read at 256kb.
thanks.