Maximum HD storage

[dryfly]

I use a WD Purple 4tb HD as storage for video management software. I have read where it is not advisable to completely fill up a HD. How close can I go to the total available space with his drive?

 

[Elixer]

You can fill it up to max.

On a SSD on the other hand, it is better to leave a 5 or so percent cushion so the SSD still has some room to move things around / garbage collection and the like.

 

[eton975]

You can fill it up to max.

On a SSD on the other hand, it is better to leave a 5 or so percent cushion so the SSD still has some room to move things around / garbage collection and the like.

Well the thing with filling up a HDD to max is that the R/W head is moving towards the centre of the platter and thus the circumference of the region it's flying round gets smaller and smaller as the HDD continues to fill up. The head's flying over less sectors = less data flown over per second = lower speed.

In theory the read/write speeds at any part of the platter could be very precisely estimated by dividing the region's circumference by the circumference of the platter's edge. In practice this is imprecise due to platter defects/bad sectors that come from the factory.

I would say a good rule of thumb is that the last few GB of most HDDs will have a R/W speed of 1/2 to 1/3 of the platter's edge. So if you benchmark your new empty drive divide that by 3 for a worst-case scenario.

 

[fleshconsumed]

I use a WD Purple 4tb HD as storage for video management software. I have read where it is not advisable to completely fill up a HD. How close can I go to the total available space with his drive?

It is not advisable because read/write performance start to suffer. The closer you get to full drive the more fragmentation you get and your read/write goes down exponentially as your hard drive struggles to find continuous space to write the data to. However, if all you're doing is just filling the drive with data to full capacity and then putting it away for storage, then there is absolutely no harm.

 

[corkyg]

Another consideration for HDDs is optimization. If it is filled, that becomes very difficult in that there is no free space that files can be temporarily moved to.

 

[Elixer]

Well the thing with filling up a HDD to max is that the R/W head is moving towards the centre of the platter and thus the circumference of the region it's flying round gets smaller and smaller as the HDD continues to fill up. The head's flying over less sectors = less data flown over per second = lower speed.

Yes, that is how physics works, the more data you write to fill up the drive, then it has to slow down as it gets filled up.

He was just asking what is the max for a WD Purple, and that is basically the whole drive.
The purple is usually for surveillance, and that is one long stream of data, so, fragmentation is a non issue, there isn't lots of deleting going on here.
They even got a special mode for doing this kind of workload.