3 ms·
> If you encrypt at a lower level than the filesystem then you're at the mercy of that lower level's error correction, but in practice it is rare to encrypt at
by colejohnson66 5y ago
> If you encrypt at a lower level than the filesystem then you're at the mercy of that lower level's error correction, but in practice it is rare to encrypt at a lower level.
My understanding is that many SSDs do encryption transparently. The ATA protocol even has a “SECURE ERASE” command that instructs the drive to wipe just the encryption key. This allowed even “bad blocks” to be erased securely.
- willis936 5y agoSSDs have a lot more aggressive error correction than most filesystems because they anticipate a high error rate and are constantly changing the map of logical blocks to physical blocks. Tapes at rest don't have to worry about that though.
- danachow 5y ago> SSDs have a lot more aggressive error correction than most filesystems Most filesystems do not do any error correction. ZFS, btrfs, ReFS, bcachefs are a few notable exceptions. And for the most part these schemes are for multiple device resilience - which is architected quite differently from the schemes used in an SSD or tape (yes, even tape). > Tapes at rest don't have to worry about that though. This isn't really true. Pretty much every physical medium at the densities used in modern time requires robust error correction because all physical media has flaws either manufactured or acquired from wear and degradation. For instance, modern LTO tapes use relatively robust 2D Reed-Solomon forward error correction similar to DVD/Blu-Ray.