--- name: BlockStorage-mounting_rhel9 title: Mount iSCSI volume on Red Hat Enterprise Linux 9 description: Learn how to mount an Block Storage for Classic volume on RHEL 9 with multipath I/O for redundant, high-performance storage access. last-updated: 2026-06-10 --- > ## Documentation Index > The table of contents for this documentation set is at https://cloud.ibm.com/docs/BlockStorage?format=markdown > The index for all IBM Cloud docs is at: https://cloud.ibm.com/docs/llms.txt > Use these files to discover more information as needed. # Mount iSCSI volume on Red Hat Enterprise Linux 9 {: #mountingRHEL} {: toc-content-type="tutorial"} {: toc-services=""} {: toc-completion-time="2h"} Learn how to mount an Block Storage for Classic volume on RHEL 9 with multipath I/O for redundant, high-performance storage access. {: shortdesc} Follow the tutorial to mount an IBM Cloud® Block Storage for Classic volume on a [virtual server](https://cloud.ibm.com/docs/virtual-servers?topic=virtual-servers-getting-started-tutorial&format=markdown) with the Red Hat Enterprise Linux® 9 operating system. You're going to create two connections from one network interface of your host to two target IP addresses of the storage array. If you're using another Linux® operating system, refer to the Documentation of your specific distribution, and make sure that the multipath supports Asymmetric Logical Unit Access (ALUA) for path priority. {: tip} ## Before you begin {: #beforemountingRHEL9} 1. Make sure that the host that is to access the Block Storage for Classic volume is authorized. For more information, see [Authorizing the host in the console](https://cloud.ibm.com/docs/BlockStorage?topic=BlockStorage-managingstorage&interface=ui&format=markdown#authhostUI){: ui}[Authorizing the host from the CLI](https://cloud.ibm.com/docs/BlockStorage?topic=BlockStorage-managingstorage&interface=cli&format=markdown#authhostCLI){: cli}[Authorizing the host with Terraform](https://cloud.ibm.com/docs/BlockStorage?topic=BlockStorage-managingstorage&interface=terraform&format=markdown#authhostTerraform){: terraform}. 1. An active [VPN connection](https://cloud.ibm.com/docs/iaas-vpn?topic=iaas-vpn-using-ssl-vpn&format=markdown) is required to access to the private network of IBM Cloud and to interact with several services. 1. Establish an SSH connection to your server. The IP address, username, and password can be found in the console. From the **menu** ![Menu icon](../icons/icon_hamburger.svg "Menu"), click **Infrastructure** ![VPC icon](../icons/vpc.svg) > **Classic Infrastructure** > ** Devices**. Then, locate your server in the list and click its name to display its details. If multiple hosts mount the same Block Storage for Classic volume without being cooperatively managed, your data is at risk for corruption. Volume corruption can occur if changes are made to the volume by multiple hosts at the same time. You need a cluster-aware, shared-disk file system to prevent data loss such as Microsoft Cluster Shared Volumes (CSV), Red Hat Global File System (GFS2), VMware® VMFS, and others. For more information, see your OS Documentation. ## Update the OS and install the iSCSI and multipath utilities {: #installutilsrhel9} {: step} Make sure that your system is updated and includes the `iscsi-initiator-utils` and `device-mapper-multipath` packages. Use the following commands to install the packages. 1. Update the OS. ```sh sudo dnf update ``` {: pre} 1. Install multipath utility ```sh sudo dnf -y install device-mapper-multipath ``` {: pre} When the package is installed, enter `mpathconf --enable --user_friendly_names n` command to enable it. 1. Install ISCSI utility ```sh sudo dnf -y install iscsi-initiator-utils ``` {: pre} When the package is installed, start it with the `systemctl start iscsid` command. ## Update iSCSI configuration files {: #updateinitiatorrhel9} {: step} 1. Update the `/etc/iscsi/initiatorname.iscsi` file with the IQN from the IBM Cloud® console. 1. The following example shows how to check the current initiator name. ```sh [root@vsi4classic ~]# cat /etc/iscsi/initiatorname.iscsi InitiatorName=iqn.1994-05.com.redhat:7acdadcdc20 ``` {: screen} 1. Open the file in a text editor: ```sh vi /etc/iscsi/initiatorname.iscsi ``` {: pre} 1. Enter the IQN in the following format `InitiatorName=`, as you can see in the following example. Replace the IQN value with your own. ```sh InitiatorName=iqn.2025-11.com.ibm:sl02su1414935-v154455886 ``` {: pre} 1. Save the file (`:w`), and exit (`:x`). 1. Uncomment and update the following entries in `/etc/iscsi/iscsid.conf` by using the username and password from the IBM Cloud® console. U se uppercase for CHAP (Challenge-Handshake Authentication Protocol) names. ```sh node.session.auth.authmethod = CHAP node.session.auth.username = node.session.auth.password = discovery.sendtargets.auth.authmethod = CHAP discovery.sendtargets.auth.username = discovery.sendtargets.auth.password = ``` {: codeblock} Don't change the other CHAP settings. IBM Cloud® storage uses only one-way authentication. Do not enable Mutual CHAP. {: important} 1. Restart the iscsid service. ```sh systemctl restart iscsid ``` {: pre} 1. Validate that the configuration is correct by running discovery against the iSCSI array. Block Storage for Classic requires dynamic target discovery that uses the SendTargets method. Do not use static node configuration, as it is not scalable and can cause connectivity issues when changes are made to the storage (such as authorizing or deauthorizing hosts to LUNs). Dynamic discovery ensures that your host automatically detects any changes to the target portals. {: important} ```sh iscsiadm -m discovery -t sendtargets -p TARGET IP ``` {: pre} If the IP address information and access details are displayed, then the discovery is successful. ```sh [root@vsi4classic ~]# iscsiadm -m discovery -t sendtargets -p 161.26.99.113 161.26.99.113:3260,1034 iqn.1992-08.com.netapp:stfdal1006 161.26.99.110:3260,1030 iqn.1992-08.com.netapp:stfdal1006 ``` {: screen} ## Set up the multipath {: #setupmultipathdrhel9} {: step} You set up DM Multipath with the `mpathconf` utility, which creates the multipath configuration file `/etc/multipath.conf`. For more information about the mpathconf utility, see the [mpathconf(8) man page](https://man.linuxreviews.org/man8/mpathconf.8.html){: external}. 1. If you didn't do it already, enter the mpathconf command with the `--enable` option. ```sh mpathconf --enable --user_friendly_names n ``` {: pre} 2. Edit the `/etc/multipath.conf` file with `nano`, `vi`, or another editor of your choice. ```sh sudo vi /etc/multipath.conf ``` {: pre} 3. Add the following minimum configuration. ```sh defaults { user_friendly_names no find_multipaths on max_fds max flush_on_last_del yes queue_without_daemon no dev_loss_tmo infinity fast_io_fail_tmo 5 } # All data in the following section must be specific to your system. blacklist { wwid "SAdaptec*" devnode "^hd[a-z]" devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*" devnode "^cciss.*" } devices { device { vendor "NETAPP" product "LUN" path_grouping_policy group_by_prio features "2 pg_init_retries 50" no_path_retry queue prio "alua" path_checker tur failback immediate path_selector "round-robin 0" hardware_handler "1 alua" rr_weight uniform rr_min_io 128 } } ``` {: screen} The initial defaults section of the configuration file configures your system so that the names of the multipath devices are of the form /dev/mapper/mpath n, where `mpath n` is the WWID (World Wide Identifier) of the device. 4. Save the configuration file and exit the editor. 5. Issue the following command. ```sh systemctl start multipathd.service ``` {: pre} If you need to edit the multipath configuration file after you started the multipath daemon, you must issue the `systemctl reload multipathd.service` command for the changes to take effect. {: note} ## Discover the storage device and login {: #discoverandloginrhel9} {: step} The iscsiadm utility is a command-line tool that is used for discovery and login to iSCSI targets, plus access and management of the open-iscsi database. For more information, see the [iscsiadm(8) man page](https://man.linuxreviews.org/man8/iscsiadm.8.html){: external}. In this step, discover the device by using the Target IP address that was obtained from the IBM Cloud® console. 1. Run the discovery against the iSCSI array. ```sh iscsiadm -m discovery -t sendtargets -p TARGET IP ``` {: pre} If the IP address information and access details are displayed, then the discovery is successful. 2. Log in to the iSCSI array. ```sh iscsiadm -m node --login ``` {: pre} ```sh [root@vsi4classic ~]# iscsiadm -m node --login Login to [iface: default, target: iqn.1992-08.com.netapp:stfdal1006, portal: 161.26.99.110,3260] successful. Login to [iface: default, target: iqn.1992-08.com.netapp:stfdal1006, portal: 161.26.99.113,3260] successful. ``` {: screen} ## Verifying configuration {: #verifyconfigrhel9} {: step} 1. Validate that the iSCSI session is established. ```sh iscsiadm -m session -o show ``` {: pre} 2. Validate that multiple paths exist. ```sh multipath -l ``` {: pre} This command reports the paths. If it is configured correctly, then each volume has a single group, with a number of paths equal to the number of iSCSI sessions. It's possible to attach a volume with a single path, but it is important that connections are established on both paths to ward against disruption of service. ```sh [root@vsi4classic ~]# multipath -l 3600a0980383056716724514550666270 dm-0 NETAPP,LUN C-Mode size=20G features='3 queue_if_no_path pg_init_retries 50' hwhandler='1 alua' wp=rw |-+- policy='round-robin 0' prio=0 status=active | `- 2:0:0:0 sda 8:0 active undef running `-+- policy='round-robin 0' prio=0 status=enabled `- 3:0:0:0 sdb 8:16 active undef running ``` {: screen} If MPIO isn't configured correctly, your storage device might disconnect and appear offline when a network outage occurs or when IBM Cloud® teams perform maintenance. MPIO provides an extra level of connectivity during those events, and keeps an established session to the volume with active read/write operations. 3. List the partition tables for the connected device. ```sh fdisk -l | grep /dev/mapper ``` {: pre} By default the storage device attaches to `/dev/mapper/`. WWID is persistent while the volume exists. The command reports something similar to the following example. ```sh [root@vsi4classic ~]# fdisk -l | grep /dev/mapper Disk /dev/mapper/3600a0980383056716724514550666270: 20 GiB, 21474836480 bytes, 41943040 sectors ``` {: screen} In the example, the string `3600a0980383056716724514550666270` is the WWID. Your application ought to use the WWID. It's also possible to assign easier-to-read names by using "user_friendly_names" or "alias" keywords in multipath.conf. For more information, see the [`multipath.conf` man page](https://man.linuxreviews.org/man5/multipath.conf.5.html){: external}. {: tip} The volume is now mounted and accessible on the host. You can create a file system next. ## Creating a file system (optional) {: #createfilesysrhel9} {: step} Follow these steps to create a file system on the newly mounted volume. A file system is necessary for most applications to use the volume. Use [`fdisk` for drives that are less than 2 TB](#fdiskrhel) and [`parted` for a disk bigger than 2 TB](#partedrhel). ### Creating a file system with `fdisk` {: #fdiskrhel} 1. Get the disk name. ```sh fdisk -l | grep /dev/mapper ``` {: pre} ```sh [root@vsi4classic ~]# fdisk -l | grep /dev/mapper Disk /dev/mapper/3600a0980383056716724514550666270: 20 GiB, 21474836480 bytes, 41943040 sectors [root@vsi4classic ~]# fdisk -l /dev/mapper/3600a0980383056716724514550666270 Disk /dev/mapper/3600a0980383056716724514550666270: 20 GiB, 21474836480 bytes, 41943040 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 65536 bytes ``` {: screen} 2. Create a partition on the disk. The following example shows the creation of the partition with default values. ```sh [root@vsi4classic ~]# fdisk /dev/mapper/3600a0980383056716724514550666270 Welcome to fdisk (util-linux 2.37.4). Changes will remain in memory only, until you decide to write them. Be careful before using the write command. Device does not contain a recognized partition table. Created a new DOS disklabel with disk identifier 0x2aa2e16c. Command (m for help): n Partition type p primary (0 primary, 0 extended, 4 free) e extended (container for logical partitions) Select (default p): p Partition number (1-4, default 1): 1 First sector (2048-41943039, default 2048): 2048 Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-41943039, default 41943039): 41943039 Created a new partition 1 of type 'Linux' and of size 20 GiB. Command (m for help): w The partition table has been altered. Calling ioctl() to re-read partition table. Re-reading the partition table failed.: Invalid argument The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or partx(8). ``` {: screen} 3. Create a file system on the new partition. - The new partition is listed with the disk, similar to `XXXp1`, followed by the size, Type (83), and Linux®. Take a note of the partition name, you need it in the next step. (The XXXp1 represents the partition name.) ```sh [root@vsi4classic ~]# fdisk -l /dev/mapper/3600a0980383056716724514550666270 Disk /dev/mapper/3600a0980383056716724514550666270: 20 GiB, 21474836480 bytes, 41943040 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 65536 bytes Disklabel type: dos Disk identifier: 0x2aa2e16c Device Boot Start End Sectors Size Id Type /dev/mapper/3600a0980383056716724514550666270p1 2048 41943039 41940992 20G 83 Linu ``` {: screen} - Create the file system: ```sh mkfs.ext3 /dev/mapper/XXXp1 ``` {: pre} ```sh [root@vsi4classic ~]# mkfs.ext3 /dev/mapper/3600a0980383056716724514550666270p1 mke2fs 1.46.5 (30-Dec-2021) Discarding device blocks: done Creating filesystem with 5242624 4k blocks and 1310720 inodes Filesystem UUID: 09e7f833-32b7-4c7f-ab68-8c6083cb8a63 Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000 Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done ``` {: screen} 4. Create a mount point for the file system, and mount it. - Create a partition name `PerfDisk` or where you want to mount the file system. ```sh mkdir /PerfDisk ``` {: pre} - Mount the storage with the partition name. ```sh mount /dev/mapper/XXXp1 /PerfDisk ``` {: pre} - Check that you see your new file system listed. ```sh df -h ``` {: pre} ```sh [root@vsi4classic ~]# mkdir /PerfDisk [root@vsi4classic ~]# mount /dev/mapper/3600a0980383056716724514550666270p1 /PerfDisk [root@vsi4classic ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 4.0M 0 4.0M 0% /dev tmpfs 469M 0 469M 0% /dev/shm tmpfs 188M 11M 177M 6% /run /dev/xvda2 24G 2.0G 21G 9% / /dev/xvda1 974M 320M 588M 36% /boot tmpfs 94M 0 94M 0% /run/user/0 /dev/mapper/3600a0980383056716724514550666270p1 20G 156K 19G 1% /PerfDisk ``` {: screen} 5. To enable automatic mounting om boot, add the new file system to the system's `/etc/fstab` file. - Append the following line to the end of `/etc/fstab` (with the partition name from Step 3). ```sh /dev/mapper/XXXp1 /PerfDisk ext3 defaults,_netdev 0 1 ``` {: pre} For more information, see [An introduction to the Linux `/etc/fstab` file](https://www.redhat.com/en/blog/etc-fstab){: external}. ### Creating a file system with `parted` {: #partedrhel} On Red Hat Enterprise Linux® 9, `parted` comes preinstalled. However, if you need to, you can install it by issuing the following command. ```sh dnf install parted ``` {: pre} To create a file system with `parted`, follow these steps. 1. Start the interactive `parted` shell. ```sh parted ``` {: pre} 2. Create a partition on the disk. 1. Unless it is specified otherwise, the `parted` utility uses your primary drive, which is `/dev/sda` in most cases. Switch to the disk that you want to partition by using the command **select**. Replace **XXX** with your new device name. ```sh select /dev/mapper/XXX ``` {: pre} 2. Run `print` to confirm that you are on the correct disk. ```sh print ``` {: pre} 3. Create a partition table. ```sh mklabel gpt ``` {: pre} 4. `Parted` can be used to create primary and logical disk partitions, the steps that are involved are the same. To create a partition, the utility uses `mkpart`. You can give it other parameters like **primary** or **logical** depending on the partition type that you want to create. ```sh mkpart ``` {: pre} The listed units default to megabytes (MB). To create a 10-GB partition, you start from 1 and end at 10000. You can also change the sizing units to terabytes by entering `unit TB` if you want to. {: tip} 5. Exit `parted` with `quit`. ```sh quit ``` {: pre} 3. Create a file system on the new partition. ```sh mkfs.ext3 /dev/mapper/XXXp1 ``` {: pre} It's important to select the correct disk and partition when you run this command. Verify the result by printing the partition table. Under the file system column, you can see ext3. {: important} 4. Create a mount point for the file system and mount it. - Create a partition name `PerfDisk` or where you want to mount the file system. ```sh mkdir /PerfDisk ``` {: pre} - Mount the storage with the partition name. ```sh mount /dev/mapper/XXXp1 /PerfDisk ``` {: pre} - Check that you see your new file system listed. ```sh df -h ``` {: pre} 5. To enable automatic mounting om boot, add the new file system to the system's `/etc/fstab` file. - Append the following line to the end of `/etc/fstab` (by using the partition name from Step 3). ```sh /dev/mapper/XXXp1 /PerfDisk ext3 defaults,_netdev 0 1 ``` {: pre} For more information, see [An introduction to the Linux `/etc/fstab` file](https://www.redhat.com/en/blog/etc-fstab){: external}. ### Managing user permissions to the content of the mounted volume {: #user-group-permissions-rhel9} As a system administrator, you can manage the access to data on the mounted volume. After the file system is ready, you can refine access control by using the `chown` and `chmod` commands to assign read, write, and execute permissions to individual users and groups. For more information, see [Red Hat's tutorial: How to manage Linux permissions for users, groups, and others](https://www.redhat.com/en/blog/manage-permissions){: external}. ## Verifying MPIO configuration {: #verifyMPIOLinux} If MPIO isn't configured correctly, your storage device might disconnect and appear offline when a network outage occurs or when IBM Cloud® teams perform maintenance. MPIO provides an extra level of connectivity during those events, and keeps an established session to the volume with active read/write operations. * To check whether multipath is picking up the devices, list the current configuration. If it is configured correctly, then a single group exists for each volume, with a number of paths equal to the number of iSCSI sessions. ```sh multipath -l ``` {: pre} ```sh root@server:~# multipath -l 3600a09803830304f3124457a45757067 dm-1 NETAPP,LUN C-Mode size=20G features='1 queue_if_no_path' hwhandler='0' wp=rw |-+- policy='round-robin 0' prio=-1 status=active | `6:0:0:101 sdd 8:48 active ready running `-+- policy='round-robin 0' prio=-1 status=enabled `- 7:0:0:101 sde 8:64 active ready running ``` The string `3600a09803830304f3124457a45757067` in the example is the unique WWID of the volume. Each volume is identified by its unique WWID, which is persistent while the volume exists. * Confirm that all the disks are present. In a correct configuration, you can expect two disks to show in the output with the same identifier, and a `/dev/mapper` listing of the same size with the same identifier. The `/dev/mapper` device is the one that multipath sets up. ```sh fdisk -l | grep Disk ``` {: pre} - Example output of a correct configuration. ```sh root@server:~# fdisk -l | grep Disk Disk /dev/sda: 500.1 GB, 500107862016 bytes Disk identifier: 0x0009170d Disk /dev/sdc: 21.5 GB, 21474836480 bytes Disk identifier: 0x2b5072d1 Disk /dev/sdb: 21.5 GB, 21474836480 bytes Disk identifier: 0x2b5072d1 Disk /dev/mapper/3600a09803830304f3124457a45757066: 21.5 GB, 21474836480 bytes Disk identifier: 0x2b5072d1 ``` The WWID is included in the device name that the multipath creates. The WWID is recommended to be used by your application. - Example output of an incorrect configuration. No `/dev/mapper` disk exists. ```sh root@server:~# fdisk -l | grep Disk Disk /dev/sda: 500.1 GB, 500107862016 bytes Disk identifier: 0x0009170d Disk /dev/sdc: 21.5 GB, 21474836480 bytes Disk identifier: 0x2b5072d1 Disk /dev/sdb: 21.5 GB, 21474836480 bytes Disk identifier: 0x2b5072d1 ``` * To confirm that no local disks are included in the list of multipath devices, display the current configuration with verbosity level 3. The output of the following command displays the devices and also shows which ones were added to the blocklist. ```sh multipath -l -v 3 | grep sd ``` {: pre} * If a volume is provisioned and attached while the second path is down, the host might see a single path when the discovery scan is run for the first time. If you encounter this rare phenomenon, check the [IBM Cloud® status page](https://cloud.ibm.com/status?component=block-storage&selected=status){: external} to see whether an event that impacts your host's ability to access the storage is in progress. If no events are reported, perform the discovery scan again to make sure that all paths are properly discovered. If an event is in progress, the storage can be attached with a single path. However, it's essential that paths are rescanned after the event is completed. If both paths are not discovered after the rescan, [create a support case](https://cloud.ibm.com/unifiedsupport/cases/add){: external} so it can be properly investigated. ## Unmounting Block Storage for Classic volumes {: #unmountingLin} 1. Unmount the file system. ```sh umount /dev/mapper/XXXp1 /PerfDisk ``` {: pre} 2. If you do not have any other volumes in that target portal, you can log out of the target. ```sh iscsiadm -m node -T -p --logout ``` {: pre} 3. If you do not have any other volumes in that target portal, delete the target portal record to prevent future login attempts. ```sh iscsiadm -m node -o delete -T -p ``` {: pre} For more information, see the [`iscsiadm` manual](https://man.linuxreviews.org/man8/iscsiadm.8.html){: external}. {: tip}