Azure Virtual Machine - local temp storage (D: drive) - how much IOPS it can handle? Virtual machine size DS3 (under older generation sizes)
Azure Portal (when deploying VM) shows that DS3 supports up to 16 data disks / up to 12800 IOPS - thats fine,
But what I am interested in is it's local/temp storage 28 GB D: drive
Documentation shows that this local/temp drive is SSD, but what I can't seem to find is information on how many IOPS this drive can handle ?
More specifically, if my TempDB has requirement of IOPS up to 1900, can D: drive on DS3 VM handle that requirement ?
From this source https://docs.microsoft.com/en-us/azure/virtual-machines/sizes-previous-gen I can guess that D: is 3200 IOPS but not sure I understand it correctly...
For VM Series with premium storage a portion of the local SSD is reserved for caching of premium disks.  That's why the D3 has 200GB of Temp Storage, but the DS3 has only 28GB of available Temp storage, with 172GB reserved for disk caching.
The IOPS are similiarly shared between the Temp storage (D:) and the disk cache.  The total IOPS is 16,000, but your effective IOPS and throughput will depend on the utilization of the disk cache.  If you turn off read caching on your data disks, or they are lightly-utilized, you'll have more IOPS available for temp storage.
That's why caching and temp storage are together in the grid:
Max cached and temp storage throughput:  
16,000 IOPS 
128 MBps  
172GB cache size 
28GB temp storage