Adam Surak, an engineer from search provider Algolia discovered a bug in the TRIM implementation of some of Samsung's solid state disks. He and his team were troubleshooting data corruption issues of some of their servers and determined Samsung's firmware as the culprit.
A bug in Samsung's TRIM code apparently causes disks to zero out 512 byte blocks of data in incorrect, seemingly random location, resulting in data corruption.
Algolia ruled out other causes for the corruption by carrying out a thorough investigation of several other layers in their service's stack, including Linux's RAID implementation, kernel, and filesystem. The company also found that servers running Intel drives were unaffected by this issue.
The affected drives in use at Algolia are:
Samsung MZ7WD480HCGM-00003 (model SM843TN)
Samsung MZ7GE480HMHP-00003 (model PM853T)
Samsung MZ7GE240HMGR-00003 (model PM853T)
Samsung SSD 840 PRO Series
Samsung SSD 850 PRO 512GB
If Algolia's determinations are correct, this problem is potentially quite serious. It also wouldn't be the first SSD-related black eye for Samsung, which recently issued two separate updates to remedy the read slowdowns we've seen with the 840 EVO SSD.