[Unklejoe]

One thing I've always wondered about is how the ECC is handled on a modern SSD with regards to data retention.

SSDs often have a data retention spec that basically defines how long you have until your bits start flipping, and it usually falls off a cliff w.r.t. temperature, which can make SSDs non-ideal for offline backups.

However, I've read that reading from the SSD periodically allows it to detect these errors. Some say that even keeping it just powered on is enough.

My question is, do SSDs run some sort of internal scrub while they're powered on? I don't think so, based off of some power consumption tests I've done.

Also, if they do detect an ECC error, will they actually re-write the block in question, or just correct it and return a successful IO, while leaving the compromised data still on the media?

[andromeduck]

IIRC, it periodically scans the blocks level metadata during lulls. Reads don't take much power but for some larger drives something like 20% of activity was towards maintenance and the guaranteed retention period without power was only something like 2-3 months.