UEK vs RHCK Decision Matrix
| Factor | UEK (Recommended) | RHCK |
|---|---|---|
| Performance | 5-10% better storage I/O | Standard performance |
| Latest Features | Newer iSCSI drivers | Conservative updates |
| Ksplice Support | Zero-downtime updates | Not available |
| RHEL Compatibility | Oracle-specific | Binary compatible |
| Oracle Support | Full support | Full support |
| Stability | Production-ready | Very stable |
Recommendation: Use UEK for better iSCSI performance and Ksplice support.
UEK Version Recommendations
For iSCSI workloads:
UEK R7 (5.15+): Recommended for Oracle Linux 8 and 9
-
Enhanced multipath performance
-
Better TCP performance
-
Improved NUMA awareness
-
Latest security fixes
UEK R6 (5.4): Minimum for production
-
Stable iSCSI support
-
Good performance
-
Long-term support
Check and upgrade UEK:
# Check current kernel version
uname -r
# List available UEK versions
sudo dnf list available kernel-uek
# Install latest UEK
sudo dnf install -y kernel-uek
# Set UEK as default
sudo grubby --set-default=/boot/vmlinuz-$(rpm -q --qf '%{VERSION}-%{RELEASE}.%{ARCH}\n' kernel-uek | tail -1)
# Verify default kernel
sudo grubby --default-kernel
# Reboot
sudo rebootKernel Boot Parameters for Storage
Recommended boot parameters for UEK:
# Edit GRUB configuration
sudo nano /etc/default/grub
# Add to GRUB_CMDLINE_LINUX:
# intel_iommu=on iommu=pt
# For NUMA systems, add:
# numa_balancing=disable
# Update GRUB
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
# Reboot
sudo rebootWhy these parameters:
-
intel_iommu=on iommu=pt: Enables IOMMU passthrough for better performance -
numa_balancing=disable: Prevents automatic NUMA balancing which can hurt storage performance
These are general CPU and NUMA optimizations that improve overall system performance for I/O-intensive workloads. They do not directly affect iSCSI protocol behavior. Measure baseline performance before and after changes to validate impact in your environment.