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CVAD MCSIO 7.15 CU4 vs 1909 VDAs

Cathy Leik


We just updated our back end from 7.15 CU4 to 1909.   


We have MCS Catalogs of Win10 desktops using MCSIO still using the 7.15 CU4 VDA in production and all is working well with that.   


I've made a copy of this master image, updated it to the 1909 VDA and created a new MCS Catalog for testing.   RAM cache on both the old and new catalog is set to 256 and disk cache is 10gb.   On the new 1909 catalog the write cache drive is mapped into the session as D: and the 2gb pagefile is moved to it which is the new, as expected behavior.    The problem is that the mcsdif.vhdx reaches capacity (8gb) within an hour of the desktops being powered on - even with no one logged onto them - once the disk is full the desktop locks up as expected.


I'm not sure what's different - it's the same image, the same back end - the existing 7.15 CU4 machines show the write cache as 50% utilized on average.   Any thoughts on how to troubleshoot why the 1909 machines are filling the cache so quickly?

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We have exactly the same issue and have a case opened with Citrix for close to two months now and they are completely useless. It was Microsoft that discovered the cache disk getting filled up. To workaround the issue, I ended up increasing the cache disk to 40 GB from the original 10GB.

On another note I am curious if it is only my experience, but in my opinion, the quality of Citrix products is getting worse and worse. I have been working with Citrix for close to 20 years now and in the last 5 years or so there has been no case where I upgrade the environment (we are on CR) and not have issues. We are considering moving to Horizon View because of all that.

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I've uninstalled the VDA, ran the cleanup tool and then installed 1909 again.  So far it's much better.  I've been logged in over 2 hours and the write cache vhdx is hanging in at around 6gb.   


Separate question - do you know of anyway to mount that disk and see what's in there?  I can use resource monitor to see writes happening but would be great to see what is actually in there.

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I ended up going through all of the scheduled tasks and disabling any that had to do with windows updates, adobe updates, google updates, etc.   These updates will fill up the write cache quickly.  Some of the tasks are reenabled by other tasks that you have to use psexec to elevate to system user to disable.  Once I got that all done we haven't had an issue with it filling up.  I also increased it from 10 gb to 12gb to accommodate the page file and event logs that we moved there.

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Hello all,


I have the same issue with the CVAD1912CU3 and the new MCSIO drivers. We never had any issue with a standard configuration for our VDI 256MB/10GB. Now we upgrade the Disk Cache Size to 25GB to mitigate the fullfil of the Diskcache during the user activities.


What I notice during the test/debug, a test file of 200MB copy into C:\, increase and grow the mcsdif.vhdx up to 5 or 6 times the orifinal file size. This mean 200MB will be 1.0/1.2 GB in the mcsdif.vhdx.


Anyone have any clue about that?


thank you,




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