PowerShell to create Image File Device with SWDSK Header

[zxu]

I am trying out the SSD L2 cache with HA devices. In order to add the L2, I need to create the cache device with a swdsk header file.

I looked all the PS examples and was not able produce the swdsk header file with New-ImageFile and then Add-ImageDevice. What is the proper way to create the image file device with a swdsk header file so that I can use it as L2 cache?

Thanks!

[Boris (staff)]

zxu,

What is the output of running the CreateImageFile script inside the StarWindX folder? This should give your the desired result.

[zxu]

It creates the img file without swdsk. I am running the latest version of SW under Win2016.

I have also noticed that if the path to the image file contains mounted volume junction, StarWindX FileBrowser can not handle junction points and will start throwing errors in the SW server log. If you use the management GUI with a path containing junction point, the create image process will never finish.

[Boris (staff)]

zxu,

I confirm you can create only the IMG file with no swdsk header file. We will implement the corresponding change to this script and it will be included into the next build.
As for the second part of your message, could you please illustrate that behavior with paths?

[zxu]

You can produce the junction point like this...

Assuming you have one system boot drive and a big RAID5 hosting your StarWind SWDSK. When you format the second RAID5 drive, instead of assigning it a drive letter (say D), you mount it under C:\starwind\raid5. C:\starwind\raid5 will be a junction point in Windows terminology. It is very similar to mounting a file system under a directory under UNIX world. StarWind have difficulties handling junction points. It appears that SW is trying to derive the free space available on the file system. If the drive is assigned letter D, it is very easy to find out the available space. However, when the drive is actually mounted as junction point, the directory access path will be C:\starwind\raid5. If not careful, you may end up getting available disk space for C drive instead of the physical drive/file system mounted under c:\starwind\raid5.

[Boris (staff)]

zxu,

I have tried running image disk creation against junction point and cannot confirm the results you get. I had no issues while creating the disk either using the StarWind Management Console or PowerShell script "CreateImageFile.ps1". In my scenario, I used a 40GB underlying disk and mounted it to a folder on the C drive. The C drive had about 15GB of free space, yet I had no trouble creating a 35GB image file inside that folder.

[zxu]

No issue with creating an image file via PS under a junction point other than the swdsk file is not generated.

Via the GUI, if you create a new image file under a junction point (without attaching it to any target), this is where the issue is (if I remember correctly). It was a side discovery when debugging PS CreateImageFile was not creating swdsk. I tried to use the GUI to create an image file (hoping it will create the swdsk) without attaching it to any target. The original goal is to use the image file as L2 cache. I ran into issues and then I converted all junction points back to assigned drive letters and the GUI was able to complete.

[Boris (staff)]

I followed your steps and tried creating image files without attaching them to any target (both small and large in size) and cannot confirm your report.
Try reproducing this situation and if you can reproduce it please PM me the link to the latest StarWind log file that would cover the period of your tries.