10/28/2022 0 Comments Vmkfstools windows 10![]() ![]() Obviously we don’t want to write new data over top of the deleted data, so thankfully the tool also has a ‘-z’ option to write zeros over these blocks instead. The tool’s primary purpose is to securely delete files by writing randomized data over released blocks to prevent deleted data from being recovered. #Vmkfstools windows 10 download#SDelete is a free tool made by Sysinternals and available for download from the Microsoft site here. There are likely several different ways that this can be done, but I used the SDelete method recommended for Windows machines in VMware KB 2004155. I’d recommend running a chkdsk or fsck before proceeding. File system repair tools may need data in these blocks if there are inconsistencies detected. Because we are manipulating blocks that should be assigned as free space, it’s important that the guest file system be in good health.This process will only work on VMDK disks without snapshots. This is just a general best practice for any type of activity that manipulates a virtual disk. Ensure you have a good backup of the VM before starting.Thanks to the guest OS zeroing process, the free space can be safely identified from a VMFS perspective.īefore getting started, there are a few things to check and a few safety precautions that I want to call out: Next, we get ESXi to look for any ‘zero’ blocks of data occupied by the VMDK disk, and release that free space back to the datastore.This essentially destroys any lingering data and makes the free space identifiable. First, we need to instruct the operating system to overwrite the ‘freed’ blocks with zeros.That said, reclaiming the space is a two step process: How can the underling VMFS datastore know which NTFS blocks contain actual data and which can be overwritten in the future? It can’t. From the perspective of ESXi, nothing really happened to that VMDK – data is still stored in those same locations despite files being deleted in the guest OS. the data stored there is no longer needed and can be replaced with new data in the future. #Vmkfstools windows 10 iso#In the example of my Windows jump box, the deletion of OVA and ISO files simply instructed the underlying NTFS filesystem to make those blocks available to be overwritten. There are a few reasons for this, but the important thing to remember is that when space is freed in the guest operating system, it doesn’t mean that those blocks no longer contain data. ![]() They don’t shrink on their own to release freed disk space. Unfortunately, as you can see, thin VMDKs only expand. Thin provisioned disks are designed to expand and consume more disk space as the virtual machine requires. Using the ‘du’ command – for disk usage – we can see the flat file containing the data is still consuming over 43GB of space: du -h *flat*.vmdkĪlthough this certainly isn’t a new topic, and has been covered elsewhere, I wanted to document my own experience with this process and provide some extra context in case it may be helpful. rw- 1 root root 8.5K Feb 16 15:26 jump.nvram rw- 1 root root 50.0G Feb 16 17:55 jump-flat.vmdk rw- 1 root root 3.1M Feb 12 21:50 jump-ctk.vmdk In this case, the disk has been expanded to 50GB: ls -lhaĭrwxr-xr-x 1 root root 3.0K Feb 12 21:50. Notice below that doing a normal directory listing displays the maximum possible size of a thin disk. Despite freeing up lots of space, the VM’s VMDK was still consuming a lot more than 26GB. After this, I had about 26GB used and 23GB free – much better.īecause that jump box is sitting on flash storage – which is limited in my lab – I had thin provisioned this VM to conserve as much disk space as possible. I expanded the disk by 10GB to take it from 40GB to 50GB, and moved off all the large files. I had downloaded a bunch of OVA and ISO files and had forgotten to move them over to a shared drive that I use for archiving. I recently ran into a situation in my home lab where my Windows jump box ran out of disk space. Not only do they allow over-provisioning, but with the prevalence of flash storage, performance degradation really isn’t a concern like it used to be. Using thin provisioned virtual disks can provide many benefits. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |