When is a hard drive/partition too full?

[daufoi]

Hello, I've heard that when a hard drive gets more than 75% full, performance will begin to suffer. My main hard drive is 73% full over 3 partitions. 2 of those partitions are 80% full. Will the performance of the 2 partitions suffer since they are over 75% full?

 

[jitpublisher]

Performance starts to suffer the minute you start putting stuff on it. Percentage wise it depends on big the drive is. 25% of a 1 TB drive is over 200 gig, and that is still a lot of room. When you get to about 10% of open space left, you really should start a looking at another solution. Besides, you are the one using it, have noticed any huge slowdowns, or have you gotten the drive is getting too full message?

 

[gtvr]

It's really more of an issue if you are deleting & rewriting a lot, which could lead to more fragmentation.

 

[jaguarskx]

As gtvt implies, performance degredation typically occurs if the files on your disk is fragmented and your drive is nearly full. That potentially means the drive heads would need to scan entire sections of the drive to search for sequential file fragments. That can take up a lot of time.

If you constantly write and delete data, then your hard drive will eventually become very fragmented and that is when you need to worry about performance. If you merely write data to the drive with little or no deletion, then you don't really need to worry about having a fagmented drive and degraded performance. For example, I store a lot of encoded movies on the hard drives within my HTPC. I basically just write data to those drive and hard drive basically writes data sequentially. In addition, I have not erased anything either so the chances of my 1TB hard drives having even the slightest amount of fragmentation is minimal.

My theoretical rule of thumb for 1TB drive is to leave about 10GB - 20GB of free space on them for defragging purposes should the need come up. I say theoretical since I haven't reached that capacity yet and my hard drives have very, very minimal fragmented files. If defragging seems slow, then I would move several GB of data onto another drive and then start defag again. Once the defrag is complete copy that the data back to the original drive whch should be written sequentially.

 

[pjmelect]

You need 15% of your hard drive free to do a drive defragment although some third party software can manage with only 5% free so it is best to have at least this much space free.

 

[jaguarskx]

Really, 15%?

Glad I just write to my 1TB drives. No re-writes or over-writes.

 

[JackNaylorPE]

Really, 15%?

Glad I just write to my 1TB drives. No re-writes or over-writes.

You have never deleted a file ? Every time you run windows update or update a program, you delete files, rewrite files. Every time you edit / save, you are rewriting / over writing files. Every time you defrag you are rewriting / over writing files. You page file is overwriting areas of the disk constantly......your temp files are always being written over.

And yes, below 15% degragging gets a bit strenuous.

I'd recommend that those concerned about disk space and performance:

1. Frequently run "Cleanup" on your HD http://www.stevengould.org/index.php?Itemid=69&id=15&option=com_content&task=view
2. Use a background defaragger.
3. Dump those "$NTuninstall...." files in your windows directory