LVM + Couldn't create temporary archive name

You may be able to circumvent the space requirement for this operation by disabling the metadata backup with the -A|--autobackup option:

lvextend -An -L+5G /dev/mapper/vg08_root

If you do this, follow the operation with a vgcfgbackup to capture the new state.

Post-mortem note:

Since the ultimate goal was to expand the logical volume and resize the encapsulated filesystem, a one-step operation could have been used:

lvextend -An -L+5G --resizefs /dev/mapper/vg08_root

In this case, the filesystem type would have been automatically deduced, avoiding trying to use resize2fs in lieu of `xfs_growfs'.

It is because there is no space in the /etc/lvm/archive or it is read only.

Judging with the partition being 100% full, /etc/lvm/archive has no space left. You will have to create some space in the root partition.

If it still does not work, means that the folder is read-only. Resolve using : chmod a+r /etc/lvm/archive