A reader asks: How much open space does a drive really need?

Reader Liz G asks (via the CONTACT link) how much open space a drive really needs:

I know installed hard drives need 15% breathing room. How about portable external hard drives? I have 7 Western Digital drives ranging in size from 500GB to 2TB and the only thing on them are images of the seven different Windows computers in the house. (done outside of Windows using Acronis True Image). Since I don’t defrag them and periodically simply remove the oldest images, can I get by with less than 15%?

How about USB sticks? At present we have between 45 – 60 of those with files and archived Windows patches and old programs.

It’s great to see you back offering advice again!

Thanks, Liz!

The 15% rule of thumb is mainly to allow space for active file copying/processing operations; and for things like pagefile expansion and tmp file creation.

If a drive is being used for simple read/write, mostly-inert file storage in the way you suggest — files come and go, but aren’t defragged or processed on the drive in question; and if that drive also isn’t where you have a pagefile or temporary file area; then I see no reason why you couldn’t use the drive to nearly its full capacity.

On larger drives and drives with high-value data, you might want to leave a little space — 2%? 3%? — as a “just in case” measure. That way, you’re not down to your last byte with no room at all in case something happens — say, the drive needs to remap some bad sectors, or something. With just a skosh of free space, your drive (and its files) will still be fine.

On low-capacity drives, including near-disposable USB media, fill it up! Might as well wring every last byte of storage out of ’em while you can!

Interesting question, Liz, thanks!


Permalink: https://wp.me/paaiox-cC

Reply? Questions? Use the Comment box at the bottom of the page, or click CONTACT.

6 Replies to “A reader asks: How much open space does a drive really need?”

  1. Great answer, Fred. Very sensible. I hadn’t thought of the idea of “inert” file storage, but you are right – if the drive is not your normal Windows drive, no need to leave much free space on it. Also, the 15% rule is good policy for the normal Windows drive, for the reasons you stated.

    Good to see you back, Fred. I was a Langa List member before you joined forces with Windows Secrets.

      1. Thanks Fred! The best part about this restart is reconnecting with long-term all the around good guy, you. 🙂
        You were my ‘Advanced Windows 101’ teacher. From your then (and I assume now) mantra “backup,backup,backup” to photo spreads of your trips and stories of “Tune-up” at a readers place I am sure I speak for many when saying WELCOME BACK!
        always, and still a life member

        1. Yours are the only sites I have kept following all of these years. I commend you on your ability to leave Computerese argot behind when you discuss computer issues. Thank you.

Comment? Question? Reply...?