Extend an LVM Logical Volume When It's 100% Full

Quick one-liner: Your LVM volume is at 100% and lvextend fails with "metadata archive failed". Here's the quick fix — disable autobackup and extend anyway.

🤔 Why This Matters

When an LVM logical volume fills up completely, extending it should be straightforward. But if there's no free space left on the volume group either, lvextend fails with a cryptic error:

# lvextend -L+5G /dev/mapper/vgname-lvname
Couldn't create temporary archive name.
Volume group "vgname" metadata archive failed.

This happens because LVM tries to create a metadata backup before making changes — and if the disk is completely full, even that backup can't be written.

The fix is simple: disable autobackup with the -An flag.

🔧 The Fix: Disable Autobackup

# lvextend -An -L+5G /dev/mapper/vgname-lvname

The -An flag tells LVM: don't create a metadata backup before this operation. Since you already have free space on the physical volume (you're just extending into it), this is safe.

Then resize the filesystem:

# For XFS
xfs_growfs /mount/point

# For ext4
resize2fs /dev/mapper/vgname-lvname

🔍 Understanding the Error

LVM keeps metadata archives in /etc/lvm/archive/ and /etc/lvm/backup/. Before any volume change, it writes a backup so you can roll back if something goes wrong.

When the volume group is at 100%, there's no room to write even this small backup file. LVM refuses to proceed, which is actually a safety feature — it prevents you from making changes you can't undo.

But when you know you have free space on the underlying physical volume (maybe you added a new disk, or you're extending into unallocated space), you can safely skip the backup with -An.

✅ When You Have Free Space on the Volume Group

If your volume group still has free extents, the normal extend works fine:

# Check free space
# vgs
  VG     #PV #LV #SN Attr   VSize  VFree
  vgname   2   3   0 wz--n- 50.0g  5.0g

# Extend normally
# lvextend -L+5G /dev/mapper/vgname-lvname
  Size of logical volume vgname/lvname changed from 10.00 GiB to 15.00 GiB.

The -An flag is only needed when the volume group itself is full or the metadata archive can't be written.

🔧 When You Need to Add Physical Storage First

If your volume group is truly full (no free extents), you need to add storage first:

# Add a new physical disk
# pvcreate /dev/sdb1
# vgextend vgname /dev/sdb1

# Then extend the logical volume
# lvextend -L+5G /dev/mapper/vgname-lvname

Then resize the filesystem as shown above.

✅ Quick Reference