I have a trio of servers that like to reboot during high disk / network IO operations. They don't appear to panic, as I have kernel.panic = 0 in sysctl.conf. The syslog just shows normal messages, like samba complaining about browse master and then just syslogd starting up. The machines seem to crash when I'm not near the console, usually when I'm trying to pull data off them to another machine running backups. But, they've also crashed trying to copy data off them to other servers (via iscsi). Also, they have crashed being on the receiving end of data via nfs. Two of the servers are linked using drbd and heartbeat, the third is stand alone. Centos 5.4 x86-64 is the flavor of linux on all of them, pretty much vanilla except for the drbd/iscsi stuff. I want to go after the motherboard manufactorer, since I'm more willing to suspect three mobos in a bad lot than three CPUs, especially since one cpu is completely different than the other two. The other variable is the two machines running drbd have promise raid cards in them. I also have the same raid card in my personal server at home. That server also has a nack of crashing during heavy disk IO to the raid volume. The entire OS doesn't crash, just the raid volume, and the only way to bring it back is a reboot. I'm really at a loss on what to do next... Any suggestions? Gordon The hardware config of the drbd servers: Tyan i3210 ICH9 mobo Intel C2D 7500 cpu 4GB A-Data ram Promise ex8650 raid Supermicro 742TQ-865 chassis (865w psu) 8x 1Tb western digital green power drives The third machine: Tyan i3210 ICH9 mobo Intel C2Q 9400 cpu 8GB Mushkin ram dmraid 5 Antec something or other chassis 550W PC Power and Cooling PSU 7x 250gb seagate 7200's