Full hard drive = Performance loss? AKA - How full are your media drives?

This is kind of a general hardware question, but I wanted to ask it here due to the situation.

Basically, I'm curious of how much of a performance loss you get by having a hard drive "full". Over the years, I've always heard things like, "If your hard drive is more than X % full, you will start to notice a performance decrease". Whether it's 50%, 75%, 90% or whatever, it seems to be all rule of thumb.

I ask this because I have 2 2TB drives that are nearly full. One has 180GB free, the other has 225GB free. They are only used to store my MKV movie files, so I wouldn't exactly consider them high usage. I will need to add more storage for sure, but at my current rate of adding media to these drives, they have enough free space to last another 6 months before I would be forced to add additional drives. Also, one of the drives is for DVD rips (The one with 180GB free). Since I am pretty much doing everything in HD these days, an additional drive for DVD rips really isn't needed.


This leads me to my questions:

1 - How full do you keep your media only drives?

2 - Am I crazy for keeping them this full, or am I worrying about a performance decrease that is mostly in my head?

3 - If there is a performance decrease, is it more applicable to certain types of usage such as daily computing vs. media storage?

it's more of a big deal if your OS is on the drive.

my 1TB drive is a bit over 70% full, it also contains my OS. i get all sorts of weird crashing problems when the drive is crunching away working hard and then windows gives me an attitude. i suspect it's a mixture of having a green drive that sleeps, having the slow wake time, and then having the drive full making it performance too slow for windows to be happy.

i run a windows home server i store all my files on there so i can keep as few files on my computer as i can to keep speed up more so for when i move to ssd with the new system build

Defrag does not work if a drive does not have more than 15% of free space (I think that is correct).

I fill my media drives to 90% more or less. A 2TB drive shows 181GB free space of 1.81TB. That gives me space to move files from drive to drive when I reorganize my movies.

af22 said:

it's more of a big deal if your OS is on the drive.

my 1TB drive is a bit over 70% full, it also contains my OS. i get all sorts of weird crashing problems when the drive is crunching away working hard and then windows gives me an attitude. i suspect it's a mixture of having a green drive that sleeps, having the slow wake time, and then having the drive full making it performance too slow for windows to be happy.

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You have a good point, it's probably only an issue when you are talking about the OS drive. I feel dumb that I didn't think of that because I have done enough desktop support over the years to know first hand that windows will do some crazy shit if you fill up the OS drive.

I guess my curiosity is based more on long term issues on a non OS drive. Everything seems to be fine as is, but I don't think I will be pushing it past the 90% full range. Every time I have filled a drive up before, it was a temporary situation while I was moving files. I guess I wanted to make sure I wasn't going to get bit in the ass by something I didn't think of by permanently keeping the drive full like it is.

GeorgeHR said:

Defrag does not work if a drive does not have more than 15% of free space (I think that is correct).

I fill my media drives to 90% more or less. A 2TB drive shows 181GB free space of 1.81TB. That gives me space to move files from drive to drive when I reorganize my movies.

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Not to concerned about defrag, but good to know. I have never defraged the media drives before and windows always says it's not needed. Looks like my gut feeling was correct and going over 90% full is starting to ask for trouble. I have a full backup of the drive just in case, but I'm not interested in pushing my luck for a few extra GB.

It can be a problem in certain circumstances like moving a file onto the drive (might take longer) and when trying to defrag (there needs to be free space to move the files around; you usually want 10-15% free space for defragging).

Otherwise It's not that big of a deal for just reading data off the drive. To me a full drive just signals it's time to buy another HD.

xFROSTx said:

T
This leads me to my questions:

1 - How full do you keep your media only drives?

2 - Am I crazy for keeping them this full, or am I worrying about a performance decrease that is mostly in my head?

3 - If there is a performance decrease, is it more applicable to certain types of usage such as daily computing vs. media storage?

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1 - As full as they need to be. I've maxed out all my media drives at some point.

2 - No. There is a performance decrease for stuff for items on the inside of the platters but unless your having to move large amounts of data a lot you won't be able to tell.

3 - Only applicable to moving lots of data. Watching a ripped blu-ray won't be any different. Copying the same blu-ray to another drive will take longer because your read speed will be reduced on the inside of the platters.

As an example - When my 2TB drive wasn't full I could transfer stuff at 70-80MB/sec. Once I filled it I was doing 40-50MB/sec for stuff that I had transferred onto the drive recently.

My 2TB drives are full down to the last gigabyte. As discussed since they are only used for storage & backup any performance hit is pretty much null if you're doing all your main file work on your system attached data drives (editing, archiving, building, etc) then dumping them off.

I'd also like to follow the 15% rule and the addition of then being able to defrag would be nice. But, I'm holding out for the 4TB drives to come out before I get anymore drives.

visionviper said:

As an example - When my 2TB drive wasn't full I could transfer stuff at 70-80MB/sec. Once I filled it I was doing 40-50MB/sec for stuff that I had transferred onto the drive recently.

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Bingo! That's exactly what I saw. My curiosity grew as I thought about it, which prompted my questions. I decided to ask here because general searching didn't help much - it's a pretty vague topic and I felt like this was a pretty specific situation. I find it funny that you called it out spot on.


Every month or two, I do a full backup of my media drives (TV1, TV2, Movies1, Movies2) to spare drives (Kept in a closet) via an eSATA docking station. Yeah, my backup procedures are a little paranoid, but I've lost enough drives over the years, that I don't trust it as a backup if it's plugged in to anything. Anyway, when I started doing my backups recently, I noticed that Movies1 (225 GB free) took almost 6 hours to completely backup when I thought it only used to take 4. When Movies2 (180 GB free) also took 6 hours, I noticed the transfer rate was only 40ish MB/sec. I thought the 70-80MB/sec I remembered getting must have just been in my head, until I saw that TV1 and TV2 (Which are only half full each) copied at 70-80MB/sec. That's when I decided to look into this more. If it doesn't hurt anything, I don't care. I can deal with it if it only really affects how long it takes to do a backup. I was just concerned since it was out of the ordinary and I wanted to make sure I wasn't asking for problems.

Perhaps doing a full backup is not necessary. You should only need to do incremental backups.

GeorgeHR said:

Perhaps doing a full backup is not necessary. You should only need to do incremental backups.

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This is normally true. I did full backups this time because I rearranged a bunch of my media files and the folder structures and doing a full backup just seemed easier. I don't care too much how long it takes, since I usually do the backups before I go to bed or something.