ENABLE KEYS on a large table is crashing mysql
When I asked Question 4: (During the ENABLE KEYS phase, do you see Repair by keycache in SHOW PROCESSLIST?) this is what happens when there is no more room for sorting. You most likely ran out of room if mysqld attempted to switch to Repair by keycache.

If you are stuck with this 2GB Server for testing, try one or more of the following:


Lower bulk_insert_buffer_size to 64M
mysqldump the original data using --skip-extended-insert and reload with it. It will produce one INSERT per row. It will be slower to reload (about 2-3 timer longer) but at least memory will be spared collateral damage
Abandon doing DISABLE KEYS and ENABLE KEYS