Commands
Table of Contents Introduction Redhat recently introduced the System Storage Manager (SSM), a unified user interface that allows uses to manage complicated systems in a
Learn how to configure LVM on multipath devices in RHEL with this comprehensive step-by-step guide. Improve storage performance, ensure high availability, and master enterprise-level disk management using MPIO and LVM.
When building enterprise-level storage systems, logical volume management (LVM) combined with multipath I/O (MPIO) ensures robust redundancy, scalability, and high availability. Red Hat Enterprise Linux (RHEL) supports both technologies natively, making it a powerful platform for storage-heavy workloads.
In this guide, we’ll walk through a comprehensive, from-scratch setup to configure LVM on multipath devices in RHEL, optimizing for both performance and resilience.
Multipath I/O (MPIO) |
Multipath I/O allows Linux to access storage devices over multiple paths, typically via iSCSI or Fibre Channel SAN. If one path fails, traffic reroutes automatically.
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LVM abstracts the physical disk layer into flexible, resizable storage units:
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| Feature | Multipath + LVM |
|---|---|
| Redundancy | ✓ |
| Flexible Resizing | ✓ |
| Snapshots | ✓ |
| Performance | ✓ |
| Load Balancing | ✓ |
| Dynamic Path Management | ✓ |
Photo by admingeek from Infotechys
Ensure the following before starting:
| Requirement | Description |
|---|---|
| OS | RHEL 8 or RHEL 9 |
| Storage | Access to SAN or iSCSI LUNs |
| Permissions | Root or sudo access |
| Tools | lvm2, device-mapper-multipath |
Step 1: Install Required Packages |
sudo dnf install -y device-mapper-multipath lvm2
Enable multipath support:
sudo mpathconf --enable --with_multipathd y
Step 2: Identify Multipath-Capable Devices |
Use the following command to check available paths:
sudo multipath -ll
Example output:
3600508b400105e210000900000490000 dm-2 IBM,2145
size=100G features='1 queue_if_no_path' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=50 status=active
| |- 2:0:0:1 sdb 8:16 active ready running
| |- 3:0:0:1 sdd 8:48 active ready running
✅ The device name |
Step 3: Configure Multipath |
Create or edit the multipath configuration file:
sudo vim /etc/multipath.conf
Example minimal config:
defaults {
user_friendly_names yes
find_multipaths yes
}
Restart the service:
sudo systemctl restart multipathd
Step 4: Enable and Start Services |
sudo systemctl enable --now multipathd
Check service status:
sudo systemctl status multipathd
Step 5: Create Volume Groups and Logical Volumes |
Now use the multipath name to initialize LVM.
sudo pvcreate /dev/mapper/mpatha
👀 Replace |
sudo vgcreate vg_multipath /dev/mapper/mpatha
sudo lvcreate -L 50G -n lv_data vg_multipath
sudo mkfs.xfs /dev/vg_multipath/lv_data
sudo mkdir /mnt/data
sudo mount /dev/vg_multipath/lv_data /mnt/data
Add to /etc/fstab for persistent mount:
/dev/vg_multipath/lv_data /mnt/data xfs defaults 0 0
🧪 Verifying the Configuration |
Use these commands to verify multipath and LVM:
| Command | Purpose |
|---|---|
multipath -ll | Show active multipath devices |
lsblk | See logical volume layout |
vgs, lvs, pvs | View LVM hierarchy |
cat /proc/mounts | Confirm mounted volume |
Example:
sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
mpatha 252:0 0 100G 0 mpath
├─vg_multipath-lv_data 253:1 0 50G 0 lvm /mnt/data
🧠 Best Practices |
| Practice | Description |
|---|---|
| Use UUIDs or aliases | Avoid device name mismatches after reboot |
| Monitor paths | Use multipathd -k for CLI control |
| Schedule backups | Use LVM snapshots for fast backup points |
| Disable WWID renaming | Use aliases in /etc/multipath.conf |
| Limit access | Block raw disk access in udev for safety |
Multipath Not Detecting Devices |
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LVM Not Seeing Devices |
Ensure devices are initialized:
sudo pvscan
sudo vgscan
Paths Flapping |
Use logs:
sudo journalctl -u multipathd
Consider disabling queue_if_no_path in HA setups.
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