Re: [savannah-help-public] GNU Emacs repository corrupted on savannah

[Paul Eggert]

Bob Proulx wrote:
> The FSF admins have isolated and corrected the problem.  The report is
> that the problem was a faulty SSD in a RAID10 set of four.  It was
> returning corrupted data and reporting it as good data.  That's
> exceptionally bad hardware.

Ouch! What type of SSD it was, exactly?

I don't know of any published measurements for this type of error, though Google 
has published measures for many other types. In their experience, flash drives 
have significantly more uncorrectable errors than hard disk drives, with 
different failure characteristics for MLC vs SLC vs eMLC in the field. See:

Schroeder B, Lagisetty R, Merchant A. Flash reliability in production: the 
expected and the unexpected. FAST'16, 2016-02-22, 67-80. 
https://usenix.org/conference/fast16/technical-sessions/presentation/schroeder


For more details about flash drives problems after cycling power, see:

Zheng M, Tucek J, Qin F, Lillibridge M. Understanding the robustness of SSDs 
under power fault. FAST'13, 2013-02-12, 271-84. 
https://www.usenix.org/conference/fast13/technical-sessions/presentation/zheng