Will device-based “wear leveling” equalize access across both SSD partitions?

Question

I can’t see that my specific point is covered by the “Wear Levelling” section in the answer to the earlier question Disadvantages of partitioning an SSD?

I’ve been booting Windows 7 from a 32GB SSD for some time with no problems. I don't keep docs/data on the boot drive, so it’s barely half-full. But I just treated myself to a new 64GB SSD, mainly because the old one is noticeably slow at writing.

I want to split the new SSD into two equal-sized partitions, with the “non-boot” one only accessed occasionally using Paragon to create a full system backup of the boot drive, which I copy over my home network to a different machine for absolute security.

Will device-based “wear leveling” equalize access across both partitions? If not, I suppose I could “swap” the two partitions at some point in the future, but I’d rather not have to.

Answer 1

So long as the operating system you are using supports the trim command then unused blocks, irrespective of their logical placement on the drive, will be returned to the wear levelling pool and will therefore be available for wear levelling across the drive.

It helps to not think of an SSD as the physical drive that you partition yourself, as is the case with a standard HDD. What you "partition" on an SSD is actually the space on-top of another filesystem that itself is on top of the raw block device.

As a rather simplistic view, between you and the actual flash blocks is a flash transition layer or similar that does the wear levelling:

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It is upon this FTL layer that your partitions sit, not the actual flash.

As an example, if you were at some point to delete and repartition your drive it is entirely possible that your partition headers would get wear levelled and could potentially be placed in a completely different physical flash block than they were originally. It is up to the wear levelling algorithm to decide how and where to put any data.