We've been hit by a strange problem for about 9 months already. Our main server suddenly becomes very unresponsive, the load skyrockets and if demand is high enough it collapses. top shows many processes stuck in D state. There are no raid or disk error messages, either in the console or logs. The machine has 4 IDE disks in a software raid5 array, connected to a 3Ware 7506. Only once I saw warnings of scsi resets of the 3Ware due to timeouts. This 3Ware card has leds which are on when there's activity in the IDE channel. As expected, all leds turn on and off almost simultaneously during normal operation of the raid5, however when the problem appears one of the leds stays on much longer than the others for each burst of activity. This shows that the disk is getting much slower than the others, holding the whole array. Several times a smart test of the disk shows read failures but not always. I've changed cables, 3Ware card and even connected the slow disk in the IDE channel of the motherboard to no avail. Changing the disk and reconstructing the array restores normal operation. This has happened with 7 (seven!!) disks already, 80GB and 120GB, Maxtor and Seagate. Has anyone else seen this? - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
