# Does FreeBSD become slow when the hard drive starts to get full?



## moitetajni (Oct 7, 2015)

Hello. I am new here (in the forum and in the FreeBSD community). I have been using Linux (Fedora) for about two years and am starting to research FreeBSD with the desire to, eventually, switch to it.

*One of the doubts in my mind is if FreeBSD becomes slow when the hard drive starts to get full. *The reason I ask is because I know that the modern operating systems by Apple are based on FreeBSD and the other day, when working in the Apple computer of a friend of mine which had its hard drive almost full of data, I noticed how slow the system was; it reminded me of my days with Windows. It struck me because as a Linux user I've had my hard drive almost full with data of all sorts and it has never slowed my system down.

So I would like to ask the community if FreeBSD experiences similar problems or it is a problem of the Apple OS's alone.

Thanks for the help.


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## kpa (Oct 7, 2015)

Please stop repeating the FUD about OS X being based on FreeBSD. It is not based on FreeBSD but on an object oriented operating system named "NextSTEP" developed by Steve Jobs.  NextSTEP used the Mach kernel developed at the Carnegie Mellon University. Parts of the userland in NextSTEP were taken from the BSD Unix and later updated from FreeBSD.

https://en.wikipedia.org/wiki/History_of_OS_X


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## drhowarddrfine (Oct 7, 2015)

moitetajni said:


> I know that the modern operating systems by Apple are based on FreeBSD


The kernel is not. Parts of userland are. So, generally no, OSX is not based on FreeBSD.

The answer to your question is, it depends. ANY operating system will slow down if it needs to swap data out between the hard drive and memory. ALL of them. So it depends on what program you are running and what data you are using and how much of it. Without that knowledge, the question is unanswerable.


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## junovitch@ (Oct 8, 2015)

I've never used Apple software so I don't know what file system they use by default.  The simplistic answer for FreeBSD is ZFS, because of it's copy on write design, will lose performance as the drives get full while UFS maintain performance.  However don't base an opinion on one single metric like that as ZFS and UFS have very different design goals, implementations, and pros/cons.

Edit:  Personal experience on my media server with a 90% full pool is performance was fine.  It was mostly read only so for another workload it may have been noticeable.


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## SirDice (Oct 8, 2015)

moitetajni said:


> So I would like to ask the community if FreeBSD experiences similar problems or it is a problem of the Apple OS's alone.


It's an issue with _all_ operating systems, old and new. 

Just think about it. If the OS needs to write data and the disk has lots of free space it can easily write. When the disk gets full (and possibly fragmented) it's going to take a bit more time to find the free space to write to. The "free" bits may even be scattered all over the disk adding a lot of seek time. This slows it down, regardless of the OS.


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## fnoyanisi (Oct 13, 2015)

moitetajni said:


> I have been using Linux (Fedora) for about two years and am starting to research FreeBSD with the desire to, eventually, switch to it.


Don't make it like an "I will start my diet tomorrow" excuse, download it and start using.



moitetajni said:


> The reason I ask is because I know that the modern operating systems by Apple are based on FreeBSD


This is what Apple says about its operating system (I have to admit that I was about to buy an MBP, but too much RMS blog reading washed my brain and I ended up buying a "bargain laptop" and running FreeBSD on it)



moitetajni said:


> *One of the doubts in my mind is if FreeBSD becomes slow when the hard drive starts to get full.*
> ....
> as a Linux user I've had my hard drive almost full with data of all sorts and it has never slowed my system down


I have never had any issues with disk speed with my UFS install (daily usage). Don't want to start a "best OS fight" but my personal experience with GNU/Linux OS'es about 10 years tells me most Linux based OS'es are more demanding in terms of system resources.

As others pointed out, EVERY OS will have some difficulties when usage of some resources (disk, memory, CPU usage) is higher than a certain threshold. It also depends on your hardware; is hard drive an SSD, 5400 RPM HDD or 7200 RPM HDD?


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