NTFS permissions - hide DLL from client, but allow execution
I have Server 2022 domain controller with AD. I am sharing a folder with clients, and this folder contains the exe and dll files for an application. I have set permissions so that the exe is visible to the client user which is fine. The issue is that the dll is also visible. I want to make the DLL invisible, but the DLL can still be used when the client runs the exe. Any advise would be appreciated. SijcookeIncorrect free space on NTFS (reserved clusters)
I have a very unusual issue on my Server 2012 R2. When formatting a partition as NTFS a large part of the space is reserved (~500Mb) For example, when formatting a 1Gb partition, I only have about half of it free. This happens even when creating a new NTFS partition on a new disk, that is, it is not a case of CHKDSK I created a 1Gb test partition and the command "FSUTIL FSINFO NTFSINFO X:" returns: total reserved clusters: 128,239 (500.9 mb) I can't understand why 500.9Mb are reserved. On another machine, doing the same, you have 14.5Mb reserved, that is, the 1Gb partition has almost 100% free space. I can't understand the reason for this behavior, I don't know if this is an error or if it is caused by some feature of Windows Server 2012 R2. Thanks a lot for any help.
NTFS slow unbuffered writes during read of same file
I have an application that does high speed (>3000 MB/s) sequential unbuffered writes to large (256GB) pre-allocated files in NTFS. I also perform random unbuffered reads from this volume at a much lower rate when needed, using a block size of around 2MB. Reading and writing at high speed works perfectly almost 100% of the time. However, when I read from (a different part of) the same file that is currently being written, it causes the write speeds to suffer dramatically and queue depths to shrink below 1. The moment writing moves on to another file, the speeds pick back up to where they belong. This is confirmed on Server 2016 and 2019. This could be a difference in I/O scheduling, caching behavior, or something else that is dependent on the file system, but I can't seem to find any documentation on it. What could explain this behavior, and is there a workaround?Direct Mode didn’t work on ReFS formated Cluster Shared Volumes
Hi, why is direct access not possible with a ReFS format CSV volume? Instead of direct access, all reFS formatted CSVs that are provided by a SAN runs with "FileSystemRedirected". This behavior is critical because the "FileSystem Redirected" mode, compared to direct access, has up to 90% or more performance losses depending on the environment. Neither the fact that ReFS formatted CSV only run in "FileSystem Redirected" mode nor the associated performance penalties are mentioned in any official Microsoft statement. On the contrary, Microsoft actively recommends using ReFS for VHDX files. That is why, like many others, I have formatted the CSV with ReFS since the server in 2016, because I hoped that this would be an advantage for the customer systems. Unfortunately, this procedure led to the opposite and it was not easy to find the reason for it. Mainly because Microsoft has absolutely nothing documented about this behavior. I personally had to postpone more than 100 TB of data on various customer systems over the past few months in order to eliminate this problem and to bring the CSV formatted with ReFS back to NTFS. This action cost my company a considerable amount and also led to massive annoyance of the customer. However, if you know what to look for, you can now find a lot of posts on the Internet that confirm this behavior. Here are a few examples. https://github.com/MicrosoftDocs/windowsserverdocs/issues/2051 https://www.hyper-v-server.de/hypervisor/performance-probleme-hyper-v-cluster-mit-san-storage-und-csvs-mit-refs-formatiert/ https://techcommunity.microsoft.com/t5/failover-clustering/understanding-the-state-of-your-cluster-shared-volumes/ba-p/371889 https://www.windowspro.de/marcel-kueppers/refs-ntfs-vor-nachteile-dateisysteme-server-2016 https://www.wowrack.com/blog/microsofts-latest-system-refs-compared-to-ntfs/ https://4sysops.com/archives/windows-server-2019-cluster-shared-volumes-best-practices/ https://social.technet.microsoft.com/Forums/ie/en-US/6b2dcc4f-e735-4700-81f3-df45d94e7e01/refs-for-a-hyperv-csv-volume?forum=winserverhyperv https://forums.veeam.com/veeam-backup-replication-f2/latest-veeam-community-forums-digest-oct-2-oct-8-t46019.html Therefore, I now spare myself any further details and come directly to my demand. If ReFS does not fundamentally support direct mode, then I also expect Microsoft to publicly clarify it accordingly and also clearly indicate which disadvantages could arise if the CSVs are formatted with ReFS. If it should work and there is only a bug in between, please finally fix it. This problem has existed since Server 2016, so enough time should have passed to fix the problem. Best Regards from Germany Alex
New File Systems and Storage white papers, by Dilip Naik - MVP
First published on TECHNET on Jul 10, 2008 Dilip Naik, File Systems and Storage MVP, just released 3 new white papers: Best Practices To Avoid Fragmentation While Writing To A File NTFS and Thin Provisioning HyperV Storage Deep Dive enjoy the reading, --Malu Menezes
