My company's product is developing a product using postgres 7.4.6 on a Linux 2.6.10 or 11 kernel, (don't have the exact version handy). We do "vacuum verbose analyze" daily. Two days after the database was created and loaded with a small amount of data (megabytes), the postgres logs had this line: 2005-04-16 00:00:53 ERROR: could not read block 52 of relation "idx_ef_hash": Input/output error idx_ef_hash is an index. I believe that vacuuming is to blame based on vacuum output: 04/16 00:00:14.388 03136277 Starting daily vacuum 04/16 00:00:53.192 03136280 process failed with exit code 1. 04/16 00:00:53.193 03136281 stderr: INFO: vacuuming "information_schema.sql_features" 04/16 00:00:53.193 03136282 stderr: INFO: "sql_features": found 0 removable, 360 nonremovable row versions in 5 pages 04/16 00:00:53.193 03136283 stderr: DETAIL: 0 dead row versions cannot be removed yet. 04/16 00:00:53.193 03136284 stderr: There were 0 unused item pointers. 04/16 00:00:53.193 03136285 stderr: 0 pages are entirely empty. 04/16 00:00:53.193 03136286 stderr: CPU 0.00s/0.00u sec elapsed 0.00 sec. 04/16 00:00:53.193 03136287 stderr: INFO: vacuuming "pg_toast.pg_toast_17070" ... (The first two lines are from my application, the rest is stderr from the vacuum process.) Googling didn't turn up useful information on this problem. Can anyone tell me whether this error indicates a disk problem, OS problem, known postgres bug, or something else? We've only seen this occur once. Jack Orenstein ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend