58030ERRORTier 1 — Safe✅ HIGH confidence

I/O error

Category: System ErrorVersions: All Postgres versions

🔴 Production Risk Error

Critical: disk I/O errors can cause database files or WAL to be corrupted, leading to data loss.

What this means

SQLSTATE 58030 is raised when Postgres encounters an I/O error reading from or writing to the filesystem — typically a disk failure, full disk, or filesystem corruption. This is a serious error that may indicate hardware problems.

Why it happens

1Disk hardware failure causing read/write errors
2Filesystem corruption
3NFS or network storage disconnection causing I/O failures
4Operating system I/O error when accessing data files or WAL

How to reproduce

Disk failure during a database write.

trigger — this will ERROR

ERROR: could not read from file "pg_wal/0000000100000001": Input/output error

Fix 1: Check disk health with SMART diagnostics and repair or replace the disk

When 58030 is caused by hardware failure.

fix

Why this works

Run smartctl or the storage vendor diagnostic tools to assess disk health. If errors are found, replace the disk and restore from backup.

Fix 2: Check available disk space

When the I/O error may be caused by a full disk.

fix

SELECT pg_size_pretty(pg_database_size(current_database()));

Why this works

A full disk causes write failures. Free space or expand storage, then investigate why disk usage grew unexpectedly.

What not to do

✗

Continue running Postgres on a disk showing I/O errors

Why it's wrong: I/O errors indicate storage hardware problems; continuing risks data corruption.

Dangerous variant

⚠️ Warning

58030 during WAL write — potential WAL corruption and data loss

Sources

📚 Official docs: https://www.postgresql.org/docs/current/errcodes-appendix.html

🔧 Source ref: Class 58 — System Error

Confidence assessment

✅ HIGH confidence

Standard SQLSTATE for I/O errors. Stable across versions.