I found the below info on MFT but did not find anything about how the MFT Zone automatically allocating more space to the MFT when the current MFT Zone is consumed.
https://learn.microsoft.com/en-us/troubleshoot/windows-server/backup-and-storage/ntfs-reserves-space-for-mft As files are added to an NTFS volume, more entries are added to the MFT and so the MFT increases in size. When files are deleted from an NTFS volume, their MFT entries are marked as free and may be reused, but the MFT does not shrink. Thus, space used by these entries is not reclaimed from the disk Depending on the average file size and other variables, either the reserved MFT zone or the unreserved space on the disk may be used up before the other as the disk fills to capacity. Volumes with a small number of relatively large files exhaust the unreserved space first, while volumes with a large number of relatively small files exhaust the MFT zone space first. When the MFT needs to increase in size, for example, you created new files and directories, it is taken from the MFT Zone first, thus decreasing MFT fragmentation and optimizing MFT performance. The default MFT Zone is calculated and reserved by Ntfs.sys when it mounts the volume, and is based on volume size. You can increase the MFT Zone by means of the registry entry documented below, but you cannot make the default MFT Zone smaller than what is calculated by Ntfs.sys. Increasing the MFT Zone does not decrease in any way disk space that can be used by users for data files. George. On Tuesday, 04-02-2025 at 07:45 George at Clug wrote: > I love three letter acronyms ! So meaningful (of course, context helps) > > I am going to guess with large capacity drives, and large SAN environments, > Master File Table (MFT) management and scalability is critical ? > > I am curious: Are you storing many small files? What is the size of the > NTFS partition? What happens if the NTFS partition is resized to be much > larger? > > https://www.ibm.com/think/topics/managed-file-transfer > > What is managed file transfer (MFT)? > > Managed file transfer (MFT) is a technology platform that allows > organizations to reliably exchange electronic data between systems and > people, within and outside the enterprise, securely and in compliance with > applicable regulations. > > MFT is a more reliable and efficient means for secure data and file transfer, > outpacing and outperforming applications such as file transfer protocol > (FTP), hypertext transfer protocol (HTTP), secure file transfer protocol > (SFTP) and other methods. > > > https://www.sciencedirect.com/topics/computer-science/master-file-table > Master File Table > > In subject area: Computer Science > > Master File Table (MFT) is a crucial file in the NTFS file system that > maintains records of all files in a volume, including their directory > location, physical storage location, and metadata such as creation dates, > access dates, and file size. It is especially valuable in forensic > investigations as it allows investigators to retrieve information about > deleted files, even though the file names may not always be preserved. > > AI generated definition based on: Managing Information Security (Second > Edition), 2014 > > https://learn.microsoft.com/en-us/windows/win32/fileio/master-file-table > The NTFS file system contains a file called the master file table, or MFT. > There is at least one entry in the MFT for every file on an NTFS file system > volume, including the MFT itself. All information about a file, including its > size, time and date stamps, permissions, and data content, is stored either > in MFT entries, or in space outside the MFT that is described by MFT entries. > > On Tuesday, 04-02-2025 at 07:22 Stefan Monnier wrote: > > >> Jan 13 19:46:06 eagle ntfs-3g[4262]: No free mft record for $MFT: No > > >> space left on device > > > Hmm, MFT too small? A quick search showed me this (from a forum): > > > > AFAIK the MFT is implemented as a "normal" file; it can grow as needed > > like any other file. > > So, as long as there's room on the disk, it should not be "too small" > > (tho maybe ntfs-3g just fails to implement some growth options, > > e.g. maybe it only supports a contiguous MFT?). > > > > > Note that Dell computers we received were all delivered with 50% MFT > > > reserve. We use many large files and reducing the MFT reserve to > > > 12.5% saved these machines from being dog slow when they ‘filled up’ > > > quickly. How much MFT space is needed? *My rule of thumb for > > > estimating is ‘number of files times 4k divided by total drive > > > size’. The result is the percent of drive space needed for MFT. *As > > > you note, the actual requirement will vary… but you have to start > > > some place! > > > > Note that this "reserve" is only a strategy to reduce the risk of > > needing to use a fragmented MFT > > (https://learn.microsoft.com/en-us/troubleshoot/windows-server/backup-and-storage/ntfs-reserves-space-for-mft): > > > > Because of the importance of the MFT to NTFS and the possible impact > > on performance if this file becomes highly fragmented, NTFS makes > > a special effort to keep this file contiguous. NTFS reserves 12.5 > > percent of the volume for exclusive use of the MFT until and unless > > the remainder of the volume is used up. Thus, space for files and > > directories is not allocated from this MFT zone until all other > > space is allocated first. > > > > So the size of the "MFT reserve" can impact performance but should never > > cause a disk to appear full when it isn't. > > > > > > Stefan > > > > > >
