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The Master File Table is used by the NTFS file system to track how files are laid out on disk. The layout of the MFT itself can impact performance.[an error occurred while processing this directive]
I've heard that in NTFS there are some master tables whose size can be changed to handle large numbers of files better. I generate lots of files. How do I increase these table(s) and when?
You're thinking of the MFT or Master File Table. By default 12.5% of your hard disk space is set aside for the MFT when an NTFS drive is formatted.
If the system later needs to make the MFT larger, it will. The problem is fragmentation. Chances are very high that if the MFT grows, then it will be fragmented. Apparently it's also common that if you converted a drive from FAT to NTFS, the MFT is may be fragmented from the start. Unfortunately the defragger that is part of the operating system cannot defrag the MFT.
So is 12.5% enough? If not, how much is enough? Microsoft, in their support article How NTFS Reserves Space for its Master File Table (MFT) doesn't give any guidelines, and suggests experimenting to determine the optimal setting for your system.
But I'll make a wild approximation.
Your MFT needs are primarily a function of the number of files you'll generate and the size of your NTFS partition. MFT entries range in size from 1 to 4k, so if we assume the 4k maximum then that 12.5% on a 60 gigabyte drive can hold entries for just under 2 million files.
There is a registry setting that can be changed such that all future reformats of NTFS drives will set aside more MFT space. The instructions for changing that setting are included in the Microsoft support article I referenced above.
By the way, if 12.5% seems like a lot of space to be dedicating to the MFT, it may not be as bad as you think. Small files, I'm guessing 2k or less in size (it varies), actually reside within their MFT entry. It's only larger files that need any space outside the MFT.
So the bottom line: if you can, FORMAT, don't convert, your drives to NTFS, and if you think you'll need a larger MFT, change the registry setting before you format. If it's too late, then there is one commercial program, Diskeeper from Executive Software, that can defrag your MFT.
In addition to the Microsoft Support article I referenced above, the following resources may also be helpfull:
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