TRIM support on Macbook Pro SSD

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TRIM support on Macbook Pro SSD

Postby radupopescu » Tue Apr 19, 2016 12:53 pm

Hello,

I've recently set up a ZFS pool on the SSD of my 2014 Macbook Pro. My disk contains two slices (HFS+ and ZFS), both encrypted with FileVault2. Right now, I am interested to learn more about ZFS, this is my first experience with it. The thing that brought me to it is the lack of sparse file support on HFS+, but so far I really like the design of ZFS (pools, snapshots, datasets etc.) and working with ZFS on my notebook.

I was wondering one thing, though. Does ZFS support TRIM on an SSD drive? I'm not sure that in my particular configuration - using FileVault - it's even the responsibility of ZFS to implement TRIM, or this is done at the CoreStorage layer.

In any case, many thanks to the developers and contributors of this project for bringing this technology to OS X.

Cheers,
Radu
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Re: TRIM support on Macbook Pro SSD

Postby Brendon » Tue Apr 19, 2016 1:05 pm

Hi,

The only ZFS variant that supports TRIM today is the freebsd implementation. Everyone else is waiting for an official implementation to flow from Illumos.

Cheers
Brendon
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Re: TRIM support on Macbook Pro SSD

Postby incumbent » Thu May 12, 2016 10:00 am

Brendon (or anyone really), he's not wrong though is he?

I'd assume CoreStorage would be handling TRIM as expected underneath, but I don't know how the blocks settle in terms of being marked free or not when ZFS is on top of it. If someone were to be weird about it and create a single-device zpool on a Fusion Drive, it would likely benefit from the storage tiering because CoreStorage just knows which blocks are being hit the most and doesn't really care about the filesystem on top of it if I understand it correctly.

In OP's use case it doesn't really matter if OpenZFS on OS X supports TRIM or not, since it will never come into play?
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Re: TRIM support on Macbook Pro SSD

Postby radupopescu » Thu Mar 30, 2017 11:37 pm

I apologize for not replying on this topic for such a long time. I must have missed the email notifications that there is activity on this topic!

Thank you for the clarifications.

Best regards,
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