Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ====== iSCSI ====== **General Information** iSCSI operations on Linux. **Checklist** * Distro(s): Enterprise Linux 6/7 ---- ====== Adding Disks ===== - Get the iscsi initiator name on the client<code bash>cat /etc/iscsi/initiatorname.iscsi</code> - Use the initiator name to configure the Host Group, LUN, and Host Affinity on your storage device. (Or send the initiator name to the storage admin) - From the client, discover the available LUNs on the storage device<code bash>iscsiadm --mode discovery -t sendtargets --portal <storage-ip-address></code> - Start and enable the iscsi daemon - EL6<code bash>service iscsid start chkconfig iscsid on</code> - EL7<code bash>systemctl start iscsid systemctl enable iscsid</code> - Log-in to the LUN with the iscsi client<code bash>iscsiadm --mode node --targetname <iqn-LUN#-here> --portal <storage-ip-address>:<port> --login</code> - Create /etc/multipath.conf if it doesn't exist<code bash>mpathconf --enable</code> - Configure multipath<code bash>vim /etc/multipath.conf # Blacklist exception for your device blacklist_exceptions { # WWN of LUN via iSCSI LUN group wwid "123456789" } # Setup your storage device specifics devices { device { vendor "DELL" product "MODEL-HERE" # specify other options } } # Setup the multipath multipaths { multipath { wwid 123456789 alias friendly_name_here } } </code> - Start and enable multipathd - EL6<code bash>service multipathd start chkconfig multipathd on</code> - EL7<code bash>systemctl start multipathd systemctl enable multipathd</code> - Re-scan the scsi bus<code bash>echo "- - -" > /sys/class/scsi_host/<host_number>/scan</code> - Where <host_number> is something like: host0 (there will probably be host0-3) - The hyphens represent controller,channel,lun, so – - – indicates all controllers, all channels, and all luns should be scanned. - Verify paths<code bash>multipath -ll</code> - Add mount entry to /etc/fstab ---- ====== Clean Device Removal ====== Red Hat's recommended procedure for removing storage devices. - Ensure all files open on the device are closed<code bash>lsof | grep <devname></code> - Backup/move data as needed - Remove device from any software RAID or LVM volume - Remove device from multipath - Flush outstanding I/O (important for raw devices)<code bash>blockdev --flushbufs <device></code> - Remove references to the device from applications, scripts, etc. - Remove each path to the device from the SCSI subsystem<code bash>echo 1 > /sys/block/<device-name>/device/delete</code> - Where <device-name> can be something like 'sde' ---- ====== iSCSI Admin ====== Example iscsiadm commands. View iscsi target node IP addresses and target names <code bash> iscsiadm --mode node </code> Enable iscsi target: Login to iscsi target <code bash> iscsiadm --mode node --targetname <iscsi-target-name> --portal 192.168.1.100:3260 --login </code> Disable iscsi target: Logout from iscsi target <code bash> iscsiadm --mode node --targetname <iscsi-target-name> --portal 192.168.1.100:3260 --logout </code> Delete iscsi target <code bash> iscsiadm --mode node -o delete --targetname <iscsi-target-name> --portal 192.168.1.100:3260 </code> ---- ===== Related Multipath Commands ===== If the iSCSI device that is removed is also multipath'd, remove it from multipath configuration also. View multipath devices <code bash> multipath -ll </code> Remove (flush) an unused multipath device <code bash> multipath -F </code> After, restart multipathd to ensure it doesn't come back * EL6<code bash>service multipathd restart</code> * EL7<code bash>systemctl restart multipathd</code> ---- linux_wiki/iscsi.txt Last modified: 2019/05/25 23:50(external edit)