Differences

This shows you the differences between two versions of the page.

--- linux_wiki:iscsi [2016/01/08 17:01]
billdozor [Adding Disks]
+++ linux_wiki:iscsi [2019/05/25 23:50]
@@ Line 1: / Line 1: @@
-====== Iscsi ======
-**General Information**
-iSCSI operations on Linux.
-**Checklist**
-  * 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
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-====== 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>
-----