Different SSDs with ZFS?

H

hmmmm

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Apr 18, 2024
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Hi
I use different SSDs in my Server and I read that it should not be good with ZFS?
Is there an easy to read Article about Storage Solution and what is the best option?
Thanks
 
This is just my personal understanding of software RAID. You can use different SSDs, but you need to make sure they are the same capacity. With HDDs I think its slightly more stringent you'll want to make sure they're the same capacity, same RPM, and same cache/buffer size. Again, I might be wrong, but I've not had too much trouble with Frankenstein RAIDs in my HomeLab. I wouldn't use this in a production environment though.
 
I added an (cheap consumer TLC) to a HDD ZFS mirror (making it a 3-way mirror) and random reads improved at lot. I've been mixing drives in ZFS mirror using consumer and enterprise HDD, consumer SSD and enterprise SSD (with PLP) and it all worked (well enough as can be expected). Then again, I've been using ZFS mirrors for some time and maybe it's been sub par and I just did not notice.

EDIT: Where exactly did you read that? Please provide a link to the source.
 
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Hmm, offtopic but attaching an SSD to a spinner ZFS mirror seems a bit like coupling a Ferrari to the back of a steam train. Pool I/O is going to be limited by the slowest device.

You might get better results using the SSD as L2arc or putting a Special device mirror on the pool
 
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Kingneutron said:
Hmm, offtopic but attaching an SSD to a spinner ZFS mirror seems a bit like coupling a Ferrari to the back of a steam train. Pool I/O is going to be limited by the slowest device.
Click to expand...
Random reads (IOPS) improved a lot as recent ZFS version send more read to the fastest drive. I'm very happy with it and I don't mind if I wear out the cheap consumer TLC drive (as it's a bit over-provisioned compared to the HDDs and the system does not run that much).
Kingneutron said:
You might get better results using the SSD as L2arc or putting a Special device mirror on the pool
Click to expand...
Indeed, as I use it for PBS that would most likely be the case (have metadata and directory structure on a special device) but that would require multiple small drives (to get a three-way mirror) instead of one larger drive (to get to a three-way mirror with only 2 HDDs).
 
Thanks for replay. I heard (the rumours) from Youtube. I use different 960GB SSDs from Micron and I guess out of my Mind from Seagate,... who are all comping from old Server. I bought them used from an Company for good Price.

The major question is what should I choose when I reinstall Proxmox when it come to Raid and other Storage related Settings?
 
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