Dell EqualLogic PS6210XS EqualLogic PS Series Storage Arrays iSCSI Initiator a - Page 22

Summary of Recommended Changes Table 5. Summary of Recommended Changes summarizes the changes to Linux settings that are recommended by Dell. Table 5. Summary of Recommended Changes Area Setting Default Value Recommended Value (EQL) SCSI block devices Device timeout 30 seconds 60 seconds Per SCSI device read-ahead buffer 128KB 1024KB Per SCSI device I/O scheduler CFQ noop iSCSI settings node.session.iscsi.FastAbort Yes No iSCSI settings node.startup automatic manual Ethernet devices Generic Receive Offload on off Ethernet devices1 flow control1 auto-negotiate on Ethernet devices1 jumbo frames1 (MTU size) 1500 9000 Sysctl tunable - ARP net.ipv4.conf.ethX.arp_ignore 0 1 Sysctl tunable - ARP net.ipv4.conf.ethX.arp_announce 0 2 Sysctl tunable - ARP2 net.ipv4.conf.ethX.arp_filter 0 2 1 Verify that the network infrastructure supports these two settings (flow control and jumbo frames) before implementing them. To enable pause auto-negotiation, use the ethtool -pause ethX autoneg off command. 2 This setting is required only on RHEL version 6 and version 7 and on newer ubuntu and debian kernels. Table 6. Optional Changes lists other changes to Linux settings that Dell suggests should be applied to /etc/sysctl.conf. Table 6. Optional Changes Area Setting Recommended Value (EQL) Sysctl tunable net.core.rmem_max 16777216 Sysctl tunable net.core.wmem_max 16777216 Sysctl tunable net.ipv4.tcp_rmem 8192 87380 16777216 Sysctl tunable net.ipv4.tcp_wmem 4096 65536 16777216 Sysctl tunable net.core.wmem_default 262144 Sysctl tunable net.core.rmem_default 262144 iSCSI settings node.sessions.cmd_max 1024 iSCSI settings node.session.queue_depth 128 iSCSI settings iscsi.MaxRecvDataSegmentLength 131072 22 Configure Your Linux Operating System