clar200-unlock/IDEA.md

IDEA.md — Project Idea

What is this?

A procedure + ESP32-C3 firmware to talk to the Seagate F3 diagnostic serial terminal on two EMC/CLARiiON-locked Seagate Exos X18 SAS drives (ST16000NM004J, EMC firmware ES2264), in order to reformat them out of the locked "SS160520 CLAR200" state and back into usable 512-byte-sector drives for the tank ZFS pool.

The two drives (SN ZRS015V7, ZR511KWK) were bought from ServerPartDeals already pulled from an EMC array and never properly decommissioned. They answer SCSI INQUIRY/VPD but return Hardware Error / Internal target failure (44h/00h) to every other command — including READ CAPACITY — so no host-side software (sg_format, openSeaChest, SeaChest, firmware download) can touch them. That is fully documented in ~/bin/EMC_CLAR200_DRIVE_FIX_NOTES.md.

The only remaining DIY lever is the drive's F3 service terminal, an out-of-band UART on the PCB that bypasses the SCSI command layer entirely. This project builds the cable (an ESP32-C3 acting as a 3.3 V USB-serial bridge) and documents the F3 procedure to attempt the unlock.

Problem it solves

• tank is short on 14.6 TB+ spare disks: mirror-35 has a dead + a dying leg, and ex-mirror-38 is a bare single-disk vdev. Both need 14.6 TB disks.
• These two CLAR200 drives are 16 TB and would fix both holes — if they can be unlocked. Otherwise they're paperweights / RMA candidates.

Constraints / preferences

• Cable: ESP32-C3 already attached to steel141 at /dev/ttyACM0 (native USB-Serial-JTAG, MAC 58:8c:81:ac:f0:4c). 3.3 V logic — native match for the F3 header. No separate USB-TTL adapter needed.
• Drive location: ZRS015V7 currently in a JBOD on pve173. F3 work must be done on a bench, not in-chassis — never risk the live 549 TB tank.
• Honesty: Exos-X18 F3 dialect ≠ the well-documented 7200.11 era. The procedure discovers commands via the drive's own ? help; it does not blindly fire format commands copied from old forums.
• Fallback if F3 fails: RMA to ServerPartDeals (sold not-decommissioned), or decommission in a real EMC VNX array, or PC-3000 SAS.