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You should never fill an NTFS drive past 85%. True or False?

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TtamNedlog    0

"You should never fill an NTFS drive more than 85% full, or the Master File Table [MFT] can become badly fragmented, making the drive slow."

I read that here: http://partition.radified.com/partitioning_4.htm , and was wondering if it was true.

Also, if I partition an HDD into several NTFS partitions, is there an MFT on each partition or just one for the entire physical drive? If there is one per partition, and the above statement is true, then partitioning would severely limit usable drive space because you couldn't fill each partition past 85%.

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The_Observer    293

never heard of this, very interesting, cause i server drive is over 85% now mmmmm.

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+StevoFC    21

I know some of the computers at work are pretty full and haven't experienced any unusual slowdowns. A lot of the disk defragmenting programs, Diskeeper for example, can defragment the MFT on startup. So if that would become a problem it could most likely be fixed.

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TtamNedlog    0

What about whether or not an MFT is on each partition, or just one for the entire physical drive?

I could easily avoid filling my drive up past 85%, whether it's true or not, but if there's an MFT on each partition it could be a bit more difficult to pull off. :p

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themacattack    0

I dont know. Ive had my har drive partition filled where i had 758Kilo bytes left and it still worked quite well. then again I did notice apps wouldnt launch and such. I didnt notice much fragmenting though

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James7    659

I think PerfectDisk is also good at defragging nearly full NTFS drives. I used to go about with my drive at 95-97% full all the time, kept it defragged with PD, and never noticed any such slowdown.

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CdCViRus    0

this, my friend, is some serious royal bull****

i have several partitions, each of about 100GB. The free space on most of them is < 1MB. and I have NO slowdowns at all.

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+jamesyfx    362

I think maybe on smaller drives.. Probably doesnt apply to 40GB+

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themacattack    0

of course my part was only 77.483GB and it could of been a virus i got from a un secured network while traveling

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TtamNedlog    0

Thanks for the replies guys. I knew Diskeeper and PerfectDisk could deal with MFT fragmentation, but I wasn't really concerned with fixing it after it was fragmented. That's why I posted it here in the Hardware forum. I was just curious whether or not that statement was true, and whether or not there were MFTs on every NTFS partition. :)

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Alan Cone    11

Yeah, I've never heard of this either. I've had many different drives filled up more than 85%, all works fine.

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thejohnnyq    50

This was an issue on NT v4, and earily Windows 2000 releases. This was fixed and has not been an issue, special with Win2k3.

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Sethos    270

I think if it was a real issue, we would have heard more about it.

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+chconline    158

I wouldn't fill to the max on my primary drive, but other than that... why not? :p

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Joel    25

Maybe none of you look in your event logs, but Windows will start to complain at around 85 or 90% full. At least the servers do...

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Laura    146

I believe there is an MFT per NTFS partition (volume). You could make a partition that is FAT, for example, which wouldn't use an MFT.

This website seems to explain why eating into that last 15% of space if a bad idea but I don't know if any performance drop will be noticeable in practice.

PCGuide: Master File Table

Since keeping the MFT contiguous on the disk improves performance, when an NTFS volume is first set up, the operating system reserves about 12.5% of the disk space immediately following the MFT; this is sometimes called the "MFT Zone". This is a substantial chunk of real estate to reserve, but bear in mind that it is still usable. Regular files and directories will not use this space until and unless the rest of the disk volume space is consumed, but if that occurs, the "MFT Zone" will be used. Eventually, if there are enough entries placed in the MFT, as it expands it will use up the "MFT Zone". When this happens, the operating system will automatically allocate more space elsewhere on the disk for the MFT. This allows the MFT to grow to a size limited only by the size of the volume, but this fragmentation of the MFT may reduce performance by increasing the number of reads required for some files, and the MFT cannot generally be defragmented.

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Fugi    7

Never herd of this and i think if it were true someone would have proved it a long time ago ;).

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Xerxes    196
Maybe none of you look in your event logs, but Windows will start to complain at around 85 or 90% full. At least the servers do...

The consumers versions of Windows also do that. On XP Pro on the old laptop, when it was close to been full, Windows would complain that it was low on disk space. I used to see that alot :p these days I setup Windows with it's own partition and only let stuff that will not install anywhere else install there.

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DELTETHISACCOUNT    0
Never herd of this and i think if it were true someone would have proved it a long time ago ;).

True, but you never heard of it, so how would you know if someone proved it or not? ;)

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mentalindustries    0

Stupidest thing I've heard.

For example

750GB hard drive 15% = 110Gigs ish

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GrimReeper    2

My family computer only has 1 40GB HDD and is pretty much full as in only like 50MB free and I think its really slowed down because of this, but this is of course only one computer and doesn't prove or disprove the theory. I just solve this by having a separate HDD for my OS which isn't anywhere near full and storage drives which get to 95-100% full frequently with no problems :D

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PGHammer    853
this, my friend, is some serious royal bull****

i have several partitions, each of about 100GB. The free space on most of them is < 1MB. and I have NO slowdowns at all.

That issue was, in fact, actually *true*, but only because most earlier partition-defragmentation utilities for NTFS partitions lost efficiency when a partition was more than eighty-five percent utilized. However, starting with the current versions of PerfectDisk and Diskeeper, that is no longer the case and can be safely sent into the Recycle Bin with all the other urban legends.

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PGHammer    853
The consumers versions of Windows also do that. On XP Pro on the old laptop, when it was close to been full, Windows would complain that it was low on disk space. I used to see that alot :p these days I setup Windows with it's own partition and only let stuff that will not install anywhere else install there.

The reason for the complaint has nothing to do with how the partition itself is formatted, but with Windows' incessant hunger for swapfile space. Even though both XP and Vista are more efficient at memory usage than their NT-based predecessors (and far more efficient than any 9x version ever was), it will still complain if you put the swapfile anywhere *other* than the boot partition (even if faster partitions are available). However, you *can* reduce the sheer volume of complaints by adding RAM (having 1.5 GB of system RAM does tone things down, and 2 GB should, in most cases, bring the complaining to a halt).

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