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I'm looking to confirm the disk cache settings of a local SSD in a DS-v2 series VM. I can configure the local OS as ReadWrite, ReadOnly or None (I always leave as ReadOnly per Microsoft recommendations). I set any added SSD drives as ReadOnly or None for SQL Server, again in line with recommendations. However I am not sure of local SSD (D:) cache settings and cannot find it documented anywhere.

BenOnline
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1 Answers1

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In Azure, when you create a VM in Windows Azure you are provided with a temporary storage automatically, it provides temporary storage for applications and processes and is intended to only store data such as page or swap files. This temporary storage must not be used to store data that you are not willing to lose, and there is no way to recover any data from the temporary drive.

However I am not sure of local SSD (D:) cache settings and cannot find it documented anywhere.

We can't set cache for local SSD (D:).

About the performance, the local SSD (D:), in the case of any of the premium size VMs (DS, G, and DS_V2 series) the temporary drive is backed by a local SSD for additional performance of up to 48k IOps. And another limit about DSv2-series VM Max cached disk throughput, for example, DS1_V2 max cached disk throughput IOPS is 4000. enter image description here

Jason Ye
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  • Just checking in to see if the information provided was helpful. Please let me know if you would like further assistance. – Jason Ye Feb 14 '17 at 05:19
  • Understand fully the temporary nature of local SSD. I use it as storage location for SQL Server TEMPDB, classing this somewhat as temporary, given that TEMPDB is rebuilt upon SQL Service restart. Main thing I'm looking to understand is performance on this local SSD, compared to say P10 SSD with Read/write caching on. – BenOnline Feb 14 '17 at 13:17
  • @BenOnline unfortunately, I can't find more information about temporary SSD performance. So I setup a DS1 v2 VM, and add a P10 SSD with it, then use tool to test the speed of disks. In my test, P10 SSD have higher performance than temporary SSD, P10 SSD throughput per disk about 100MB/s, and temporary SSD about 33MB/s. – Jason Ye Feb 15 '17 at 05:53
  • @BenOnline In the case of any of the premium size VMs (DS, G, and DS_V2 series) the temporary drive is backed by a local SSD for additional performance of up to 48k IOps. I had update my answer, hope this wil help you. – Jason Ye Feb 17 '17 at 07:41