[Discuss] Full disk encryption

[blu at nedharvey.com (Edward Ned Harvey)]

> From: discuss-bounces+blu=nedharvey.com at blu.org [mailto:discuss-
> bounces+blu=nedharvey.com at blu.org] On Behalf Of Chris O'Connell
> 
> ALSO, NO FULL DISK ENCRYPTION should ever be used on an SSD drive.
>  Performance will drop by 30% and the drive's wear-leveling system and
> TRIM
> won't function correctly.

First of all, the supposed 30% performance hit takes you down from 200% to
170% performance as compared to an HDD (or whatever arbitrary numbers we
want to make up for comparing HDD vs SSD performance where SSD performance >
HDD performance).

Second of all, some OSes support TRIM on encrypted drives.  They just reduce
the size of disk they consume by some percentage, and TRIM the unused blocks
as necessary, so there are always some blocks available for use that have
been TRIM'd.

Third of all, some SSD's support the virtual size reduction as above, but do
it at the hardware level, so there are always TRIM'd blocks available.

In any of the above scenarios, the end result is no significant performance
degradation on SSD's caused by TRIM vs Encryption.