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EDIT: this got closed as being "opinion based". i disagree! the facts are, i have to choose one of five Chunk Size options when creating a RAID on Mac. i don't know which size to choose for a general purpose drive. i could use advice from those more knowledgeable on such matters on which size to choose. Not opinions, but factually & technically which size would be optimal for such purposes.

fyi: using macOS 13 Ventura on a Macbook Pro M1 Max.

i have an older Western Digital My Passport Pro with a Thunderbolt 2 interface (using an Apple Thunderbolt 2 to 3 adapter/dongle). it's the one with 2 HHD's in it.

it came setup as RAID 0 but formatted in "Mac OS Extended (Journaled)". i want to reformat it to use "APFS" instead.

so using Disk Utility, i deleted the RAID and reformatted the drives. then upon using Disk Utility's RAID Assistant, i selected the RAID type to RAID 0 and selected the two newly reformatted drives. then on the next screen (Set Properties), under where you choose the Name & Format, there's a setting to select a "Chunk Size".

i've never seen this option before (granted it's been many many many years since i needed to re-RAID something), and i can't figure out which option to select...

the Chunk size options are: 16K, 32K, 64K, 128K, or 256K.

everything i've found to read on the subject says that's determined by how big the files you're working with are. to choose a small K when working with large videos & graphics files; and to choose a large K when working with smaller text based files.

but what if you have a mix for ALL kinds of files & sizes?

what would be the optimal Chunk size for a general purpose drive?

yes, i could just choose the middle one (64K) but i don't know if that's optimally average or if leaning to the left or right of middle would be better for such a mix of file types & sizes.

i did contact WD support and instead of just telling me what Chunk Size the drives came from the factory set at, their 'only' solution is for me to download/install their disk utility app. i had problems with that app working well two computers ago, so chose to not install it on my previous & current systems. i would rather a solution to be knowledge rather than 'another' app to clutter my mac innards just for this purpose. thanks.

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    Voted to reopen. Mac users are simply not used to having to specify sector/chunk sizes etc on anything; they're simply never given the choice, the system chooses. The user accepts without even necessarily knowing what the value ever is. You can do it from Terminal… but most don't. See unix.stackexchange.com/q/118302 and zdnet.com/article/chunks-the-hidden-key-to-raid-performance [neither really gives an answer, btw]
    – Tetsujin
    Commented May 21, 2023 at 17:34
  • Thanks @Tetsujin for the reopen vote & for the info. yeah, i can't find a way to just let the system decide & i can't bypass choosing one of those options. so just trying to get a sense of which one to choose for optimal general purpose use.
    – SyberKnight
    Commented May 21, 2023 at 18:34
  • You'd have to research or rely on research others did, for example overclock.net/threads/…
    – Joep van Steen
    Commented May 21, 2023 at 18:50
  • Thanks @JoepvanSteen. i gather from that article that i should actually choose 16K. hmmm.
    – SyberKnight
    Commented May 21, 2023 at 19:14
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    THANKS EVERYONE for your comments, and THANKS to those who re-opened this. when this got closed, i asked the same thing & got a satisfactory answer there @ apple.stackexchange.com/questions/460163/… , so i guess you can close this again since the answer is at the other posting. much appreciation.
    – SyberKnight
    Commented May 22, 2023 at 20:24

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