diff --git a/sys/dev/raid/vinum/vinumio.c b/sys/dev/raid/vinum/vinumio.c
--- a/sys/dev/raid/vinum/vinumio.c
+++ b/sys/dev/raid/vinum/vinumio.c
@@ -116,6 +116,10 @@
 set_drive_parms(struct drive *drive)
 {
     drive->blocksize = BLKDEV_IOSIZE;			    /* do we need this? */
+    if (drive->partinfo.media_blksize == 0) {
+	log(LOG_ERR, "vinum: media_blksize is 0\n");
+	return EFTYPE;
+    }
     drive->secsperblock = drive->blocksize		    /* number of sectors per block */
 	/ drive->partinfo.media_blksize;