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AWS supports live EBS resize. I increased from 10G to 20G on my /dev/sdb1.

Step 1: pvresize /dev/sdb1

# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 10G 0 disk
├─xvda2 202:2 0 10G 0 part /
└─xvda1 202:1 0 1M 0 part
xvdb 202:16 0 20G 0 disk
└─xvdb1 202:17 0 10G 0 part
 ├─home_vol 253:0 0 2G 0 lvm /home
 ├─tmp_vol 253:0 0 2G 0 lvm /tmp
 ....

Step 2: pvdisplay, lvdisplay

pvdisplay
 --- Physical volume ---
 PV Name /dev/sdb1
 VG Name my_vg
 PV Size <2.00 GiB / not usable 0
 Allocatable yes (but full)
 PE Size 4.00 MiB
 Total PE 2559
 Free PE 0
 Allocated PE 2559
 PV UUID ofH9ti-Wcuo-Io4o-796q-q7s8-9Z6S-oDsoEp

and

 --- Logical volume ---
 LV Path /dev/my_vg/home_vol
 LV Name home_vol
 VG Name my_vg
 LV Status available
 # open 1
 LV Size <10.00 GiB
 Current LE 511
 Segments 1
 Allocation inherit
 Read ahead sectors auto
 - currently set to 256
 Block device 253:4

As you see, the number hasn't changed. All right... let's do lvresize.

Step 3: lvresize -L 10G /dev/my_vg/home_vol

I got this instead:

 Insufficient free space: 2049 extents needed, but only 0 available

What step am I missing?

You've partitioned xvdb, and your LVM physical volume is on the first partition (which is still only 10GB). So you need to:

1. Resize the partition to fill the disk


2. Run pvresize to pick up the new size.

Personally, on Google Compute instances with LVM, I don't bother partitioning the disk — it serves no real purpose and makes resize much harder. I'd guess the same applies to Amazon. Just put the PV on the full block device (xvdb instead of xvdb1). Then you just have to run pvresize.

To resize the partition, use your favorite partition table editor. You probably have to delete the partition and create a new one making sure the start sector stays the same. That is extremely important; being a single sector off means losing your data. Then partprobe or kpartx might be able to load the updated table into the kernel with it live, otherwise a reboot is required.

Another alternative is presumably just to attach a third virtual disk, and put another PV there. You can add it to the same volume group, and grow your LVs that way.