Hi folks, I'm having high machine load on the tgtd side, and would like to ask for help tuning. background on hardware: I have a 10 disk sw-raid10 array setup with mdadm on CentOS 6, 2 (dual)x6core E5-2620 0 @ 2.00GHz, 32GB ram target machine, dedicated gigabit interfaces multipathed, and jumbo frames mtu 9000 between my target/switch/initiators. I plan to use this for KVM storage. Local IO performance tested with bonnie++ is ~ 250MB/sec for random writes, with minimal CPU load during the test. However after I introduced tgtd and iscsi into the mix, even at speeds of ~10MB/sec coming from the initiators, my target machine load is very high 10-15. The load seems to be due to tgtd. Can someone please help me tune tgtd? Thanks in advance! target.conf: default-driver iscsi <target iqn.2014-01.com.foo.us1.storage1:vmstorage> backing-store /dev/md2 initiator-address 192.168.84.29 #kvm5 initiator-address 192.168.85.29 #kvm5 initiator-address 192.168.84.78 #kvm6 initiator-address 192.168.85.78 #kvm6 initiator-address 192.168.84.76 #kvm7 initiator-address 192.168.85.76 #kvm7 write-cache off </target> iscsi initiator side: [aamerik@kvm5 ~]$ iscsiadm -m session -P 3 iSCSI Transport Class version 2.0-870 version 6.2.0-873.10.el6 Target: iqn.2014-01.com.foo.us1.storage1:vmstorage Current Portal: 192.168.84.77:3260,1 Persistent Portal: 192.168.84.77:3260,1 ********** Interface: ********** Iface Name: default Iface Transport: tcp Iface Initiatorname: iqn.1994-05.com.redhat:65274b4cae8e Iface IPaddress: 192.168.84.29 Iface HWaddress: <empty> Iface Netdev: <empty> SID: 1 iSCSI Connection State: Unknown iSCSI Session State: LOGGED_IN Internal iscsid Session State: Unknown ********* Timeouts: ********* Recovery Timeout: 120 Target Reset Timeout: 30 LUN Reset Timeout: 30 Abort Timeout: 15 ***** CHAP: ***** username: <empty> password: ******** username_in: <empty> password_in: ******** ************************ Negotiated iSCSI params: ************************ HeaderDigest: None DataDigest: None MaxRecvDataSegmentLength: 262144 MaxXmitDataSegmentLength: 8192 FirstBurstLength: 65536 MaxBurstLength: 262144 ImmediateData: Yes InitialR2T: Yes MaxOutstandingR2T: 1 ************************ Attached SCSI devices: ************************ Host Number: 7 State: running scsi7 Channel 00 Id 0 Lun: 0 scsi7 Channel 00 Id 0 Lun: 1 Attached scsi disk sdb State: running Current Portal: 192.168.85.77:3260,1 Persistent Portal: 192.168.85.77:3260,1 ********** Interface: ********** Iface Name: default Iface Transport: tcp Iface Initiatorname: iqn.1994-05.com.redhat:65274b4cae8e Iface IPaddress: 192.168.85.29 Iface HWaddress: <empty> Iface Netdev: <empty> SID: 2 iSCSI Connection State: Unknown iSCSI Session State: LOGGED_IN Internal iscsid Session State: Unknown ********* Timeouts: ********* Recovery Timeout: 120 Target Reset Timeout: 30 LUN Reset Timeout: 30 Abort Timeout: 15 ***** CHAP: ***** username: <empty> password: ******** username_in: <empty> password_in: ******** ************************ Negotiated iSCSI params: ************************ HeaderDigest: None DataDigest: None MaxRecvDataSegmentLength: 262144 MaxXmitDataSegmentLength: 8192 FirstBurstLength: 65536 MaxBurstLength: 262144 ImmediateData: Yes InitialR2T: Yes MaxOutstandingR2T: 1 ************************ Attached SCSI devices: ************************ Host Number: 8 State: running scsi8 Channel 00 Id 0 Lun: 0 scsi8 Channel 00 Id 0 Lun: 1 Attached scsi disk sdc State: running -- Alexey Amerik -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html