Cake 1.8.0418 | Iscsi

Test the settings in a staging environment first, then enjoy smoother iSCSI performance in production. Last updated: 2026-04-18. Always refer to your Linux distribution’s documentation for kernel-specific sch_cake support.

If you manage networked storage, you’ve likely encountered iSCSI (Internet Small Computer System Interface). It’s the industry-standard protocol that allows you to send SCSI commands over an IP network, effectively turning a remote disk into a local one. But raw iSCSI can suffer from latency, bufferbloat, and poor performance under load. iscsi cake 1.8.0418

tc qdisc add dev eth0 root cake bandwidth 1Gbit diffserv4 The diffserv4 option respects your iSCSI initiator/target DSCP tags. If your iSCSI runs over a VLAN (802.1Q) or VXLAN, Cake 1.8.0418 includes improved overhead compensation, preventing miscalculations that lead to underutilization. 4. ACK filtering for high-latency paths When iSCSI spans data centers or metro Ethernet, ACK packets can flood the reverse path. Cake’s ack-filter option (refined in 1.8.0418) collapses duplicate ACKs, reducing reverse-path congestion. Practical iSCSI + Cake Configuration Here’s a tested setup for a Linux iSCSI target (e.g., LIO or SCST) serving production storage. Step 1: Identify the iSCSI-facing interface ip link show # Assume iSCSI traffic uses eth1 (10 GbE) Step 2: Apply Cake qdisc # Remove existing qdisc tc qdisc del dev eth1 root 2>/dev/null Add Cake with settings for iSCSI tc qdisc add dev eth1 root cake bandwidth 9000Mbit \ # Slightly under link rate diffserv4 \ # Honor DSCP ack-filter \ # Reduce ACK load overhead 38 \ # For typical Ethernet+IP+TCP nat # If initiators are behind NAT Note: Overhead value depends on your encapsulation. For plain iSCSI/TCP/Ethernet, start with 38. Add 4 for VLAN, 14 for QinQ. Step 3: Tag iSCSI traffic on the initiator On your initiator (e.g., Linux with open-iscsi), set DSCP for outgoing iSCSI: Test the settings in a staging environment first,

tc qdisc show dev eth1 | grep cake If it shows anything below 1.8.0418 (or 1.8.x without the patch date), consider updating your kernel or backporting the sch_cake module. iSCSI is powerful, but its performance depends heavily on network queuing. Cake 1.8.0418 turns a chaotic best-effort network into a predictable, low-latency storage fabric. By applying the configuration above, you can protect your storage traffic from bufferbloat and noisy neighbors—without expensive hardware. If you manage networked storage, you’ve likely encountered