Securefs is not getting detected in SSMS and IOMeter

[anubhav6864]

Hi,
I'm currently assessing the performance of securefs. I attempted to use IOMeter for this purpose, but I encountered an issue where the securefs mounted drive was not visible in the IOMeter tool.

Additionally, when I tried to designate the securefs mounted drive as the DATA directory for my SQL Server, I faced the same problem. The securefs drive was not visible in the list of available drives on my system.

Could you please help me understand this issue? Any assistance would be greatly appreciated.

[netheril96]

Are you on Windows and running IOMeter and SQL Server as administrator or as another account than the one mounting?

[anubhav6864]

Yes, I am on windows.
And I tried running IOMeter and SQL Server with both, as administrator and normal user but failed to detect.

[netheril96]

Currently securefs has to run as the same user accessing the files. Are you sure you are running IOMeter and SQL Server as the same user as the one mounting the directory?

[anubhav6864]

Yes, Could you please try on your end to confirm.
This is would help me understand if I am missing something.

[netheril96]

IOMeter has to run as administrator, which is a different token than the user itself. You can try mounting securefs in an elevated prompt, and IOMeter probably can see its drive now.

For SQL server, it is usually log on as a virtual account. In the below example, the account is NT Service\MSSQL$SQLEXPRESS. It cannot access the mount point if you mount as a regular user. One way to solve this problem is to start securefs as a service with https://github.com/mtkennerly/shawl and change the account to the same one as NT Service\MSSQL$SQLEXPRESS.

Another way to resolve these problems would be allowing mounting securefs as a privileged service, so all users can access the mount point. But it requires a lot of changes to securefs, may break some security model, and up until now, no one has the needs. I'll consider supporting this in the future.

[anubhav6864]

I tried running securefs and IOMeter both with elevated permissions. I am unable to see the drive in "Disk Target".
Did you get a chance to try it?
I am attaching a screenshot where J is the securefs mounted drive but same is not shown in IOMeter.

[netheril96]

If you click "Open Test Configuration", you can see the drive J:. So IOMeter can access this drive, but it somehow filters it out. Maybe because it only considers real disks, and WinFsp mount points are excluded. I suggest that you try another tool for benchmarking.

[anubhav6864]

I tried ATTO Disk Benchmarking Tool, there the drive is getting detected.