File Server OS: CentOS 5.3 (x86_64) Kernel: CentOS Plus kernel (need XFS fs drivers) The file server has a Chelsio T310 10GBASE-CX4 RNIC (rev 3) PCI Express x8 MSI-X (eth0), driver and firmware is stock from the CentOS Plus kernel. Using ethtool I have verified driver association with the 3 NICs on the system (eth1 and eth2 are not connected to any switch) Driver for eth0 driver: cxgb3 version: 1.1.3-ko firmware-version: T 7.4.0 TP 1.1.0 Driver for eth1 driver: e1000e version: 1.0.2-k2 firmware-version: 1.0-0 Driver for eth2 driver: e1000e version: 1.0.2-k2 firmware-version: 1.0-0 The last 3-4 weeks, I have noticed that the eth0 link keeps going up and down, confirmed by "dmesg" output as well in /var/log/messages (dmesg sample shown below). eth0: link down eth0: link up, 10Gbps, full-duplex eth0: link down eth0: link up, 10Gbps, full-duplex eth0: link down eth0: link up, 10Gbps, full-duplex The kernel RPM verification shows no errors # uname --kernel-release 2.6.18-164.2.1.el5.plus # rpm --verify kernel-2.6.18-164.2.1.el5.plus The hardware vendor tells me that the card either fails completely (kaput) or works - there is no grey area. He is of the opinion that the problem is with the driver. Verification of the kernel rpm tells me that all files including the cxgb3 driver file md5sum are OK. I would like to hear from anyone with the same NIC or another rev. using the same driver. Are you seeing similar link up/down in your system? How did you solve the problem? TIA -- Arun Khan