Deploy LVM Disk

This article describes the steps to deploy LVM (Logical Volume Manager) with the dedicated Longhorn disk prior to installing the CDP PvC ECS system. This is only applicable to CDP Private Cloud solution installed with ECS system.

1. Install the LVM2 package. In this example, the underlying OS is Centos7.9.

   # yum install lvm2 -y

2. Check the status of the direct attached disks in this host.

   # lsblk
   NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
   sr0     11:0    1  368K  0 rom  
   vda    253:0    0   99G  0 disk 
   `-vda1 253:1    0   99G  0 part /
   vdb    253:16   0  500G  0 disk 
   vdc    253:32   0  500G  0 disk 
   vdd    253:48   0  400G  0 disk 

3. Create a physical volume.

   # pvcreate /dev/vdb
   Physical volume "/dev/vdb" successfully created.

   # pvscan
   PV /dev/vdb                      lvm2 [500.00 GiB]
   Total: 1 [500.00 GiB] / in use: 0 [0   ] / in no VG: 1 [500.00 GiB]

   # pvdisplay /dev/vdb
   "/dev/vdb" is a new physical volume of "500.00 GiB"
   --- NEW Physical volume ---
   PV Name               /dev/vdb
   VG Name               
   PV Size               500.00 GiB
   Allocatable           NO
   PE Size               0   
   Total PE              0
   Free PE               0
   Allocated PE          0
   PV UUID               AE3Zoh-pgdd-1vKK-euUl-oELk-v6yF-jnV4X3

4. Create a volume group using the identified disk.

   # vgcreate vg1 /dev/vdb
   Volume group "vg1" successfully created

   # vgdisplay vg1
   --- Volume group ---
   VG Name               vg1
   System ID             
   Format                lvm2
   Metadata Areas        1
   Metadata Sequence No  1
   VG Access             read/write
   VG Status             resizable
   MAX LV                0
   Cur LV                0
   Open LV               0
   Max PV                0
   Cur PV                1
   Act PV                1
   VG Size               <500.00 GiB
   PE Size               4.00 MiB
   Total PE              127999
   Alloc PE / Size       0 / 0   
   Free  PE / Size       127999 / <500.00 GiB
   VG UUID               hlI7n7-tjky-Tdsp-N8RQ-Zej8-Ao6u-kqmqA2

5. Create a logical volume and use the entire disk capacity.

   # lvcreate -n lv1 -l 100%FREE vg1
   Logical volume "lv1" created.   
    
   ```bash
   # lvscan
   ACTIVE            '/dev/vg1/lv1' [<500.00 GiB] inherit
   ```text
    
   ```bash
   # lvdisplay vg1/lv1
   --- Logical volume ---
   LV Path                /dev/vg1/lv1
   LV Name                lv1
   VG Name                vg1
   LV UUID                SCYwjz-xePq-BqJK-5ctU-0N1L-PpuY-wL0o2F
   LV Write Access        read/write
   LV Creation host, time ecsworker3.cdpkvm.cldr, 2022-05-26 13:19:26 +0800
   LV Status              available
   # open                 0
   LV Size                <500.00 GiB
   Current LE             127999
   Segments               1
   Allocation             inherit
   Read ahead sectors     auto
   - currently set to     8192
   Block device           252:0
   ```text
    

6. Format the logical volume.

   # mkfs.xfs /dev/vg1/lv1
   ```sql
    

7. Create the specified directory and mount the logical volume.

   # mkdir /longhorn
   ```text
    
   ```bash
   # mount /dev/vg1/lv1 /longhorn
   ```text
    
   ```bash
   # df -kh | head -1; df -kh | grep longhorn
   Filesystem           Size  Used Avail Use% Mounted on
   /dev/mapper/vg1-lv1  500G   33M  500G   1% /longhorn
   ```text
    

8. The mountpoint is now ready to be used.

   # ls -l /longhorn
   total 0
   ```text