My storage is running out of space because of FSLogix!

Published Apr 30 2020 07:18 AM 15.8K Views

Hello guys, Gonzalo here. Today I want to talk with you about one common issue that we see here in the support center: your profile disks are taking lot of space in your storage.


When you start troubleshooting this issue, you realize that you VHDs for both Profile and Office containers are big. You look in deep to the Profile container disk and while inspecting the disk content you discover that data store there is way smaller compared to the disk size. If you inspect the Office container disk your OST file is basically consuming all the disk. You think about increasing the size of the VHDs (we will discuss the options about this at the end of this blog), but you are not sure if that is the best solution and the question remains.




First, let’s discuss some of the defaults for FSLogix. Default disk size is 30 GB for both Profile and Office containers and that means that you are expecting to have for each user up to 60 GB of data if you are using both profiles.


The second default value that we need to discuss is Disk Type and we set this to dynamic. When a dynamic disk is created, initial size will be close to the data that is stored and as you add more data, disk will keep growing till it reaches the maximum size. The “problem” comes when that data is deleted because the file disk size will remain the same and that previously used space will not be reclaimed. This is not an FSLogix issue and that is part of the maintenance that you need do with any application that uses Dynamic disks in order to remove empty blocks from a dynamically-expanding virtual hard disk file.


There are various ways for you to address this situation. If you want to do this for a few users, you can use frx command tool with the migrate-vhd modifier and you can find more information here. Another alternative is by using diskpart and the instructions on how to do it are here. But if you need to do this in a more robust way, our friend @JimMoyle published a great script that you can use and will take care of the whole directory where you store your FSLogix profiles. You can download this script here.


Now, let’s talk about Office containers. As you are troubleshooting this issue, you realize that user’s OST is taking most of the space. A few things you can be done here is:

  • Reduce the amount of mail that will be synced. By default, Outlook will sync 12 months to users' local mailbox cache (.ost). You can find more information here.
  • Limit the size of the local mailbox cache file. You can find more information about this and side effects here.

So far we have discussed some of solutions to address this situations when you are hit by any of them, but the best solution is to actually plan your FSLogix deployment. We previously mentioned that default disk size is 30 GB, but if you don’t really need your users to have a disk that can potentially grow that big or you can’t allocate that for all your users, you seriously need to consider reduce the size of the disk and configure the desired one before deploying FSLogix for your users. If you are in the situation that you already deployed FSLogix and you need to reduce the size of the disks, changing the value for Size in MBs will not impact existing profiles and you will need to move the data to an smaller disk as we discussed earlier.

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‎Apr 30 2020 09:14 AM
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