root@pve1:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sdd 8:48 1 745.2G 0 disk
├─sdd1 8:49 1 1007K 0 part
├─sdd2 8:50 1 512M 0 part /boot/efi
└─sdd3 8:51 1 744.7G 0 part
├─pve-swap 253:0 0 8G 0 lvm [SWAP]
├─pve-root 253:1 0 96G 0 lvm /
├─pve-data_tmeta 253:2 0 6.3G 0 lvm
│ └─pve-data-tpool 253:9 0 612.2G 0 lvm
│ ├─pve-data 253:10 0 612.2G 1 lvm
│ ├─pve-vm--100--disk--0 253:11 0 200G 0 lvm
│ ├─pve-vm--500--disk--0 253:12 0 30G 0 lvm
│ ├─pve-vm--101--disk--0 253:13 0 4M 0 lvm
│ ├─pve-vm--101--disk--1 253:14 0 32G 0 lvm
│ ├─pve-vm--502--disk--0 253:15 0 32G 0 lvm
│ ├─pve-vm--504--disk--0 253:16 0 50G 0 lvm
│ ├─pve-vm--102--disk--0 253:17 0 32G 0 lvm
│ └─pve-vm--501--disk--0 253:18 0 30G 0 lvm
└─pve-data_tdata 253:3 0 612.2G 0 lvm
└─pve-data-tpool 253:9 0 612.2G 0 lvm
├─pve-data 253:10 0 612.2G 1 lvm
├─pve-vm--100--disk--0 253:11 0 200G 0 lvm
├─pve-vm--500--disk--0 253:12 0 30G 0 lvm
├─pve-vm--101--disk--0 253:13 0 4M 0 lvm
├─pve-vm--101--disk--1 253:14 0 32G 0 lvm
├─pve-vm--502--disk--0 253:15 0 32G 0 lvm
├─pve-vm--504--disk--0 253:16 0 50G 0 lvm
├─pve-vm--102--disk--0 253:17 0 32G 0 lvm
└─pve-vm--501--disk--0 253:18 0 30G 0 lvm
root@pve1:~# mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,relatime)
udev on /dev type devtmpfs (rw,nosuid,relatime,size=32847152k,nr_inodes=8211788,mode=755,inode64)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,nodev,noexec,relatime,size=6576304k,mode=755,inode64)
/dev/mapper/pve-root on / type ext4 (rw,relatime,errors=remount-ro)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,inode64)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k,inode64)
cgroup2 on /sys/fs/cgroup type cgroup2 (rw,nosuid,nodev,noexec,relatime)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime)
bpf on /sys/fs/bpf type bpf (rw,nosuid,nodev,noexec,relatime,mode=700)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=30,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=14936)
mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime,pagesize=2M)
debugfs on /sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime)
tracefs on /sys/kernel/tracing type tracefs (rw,nosuid,nodev,noexec,relatime)
fusectl on /sys/fs/fuse/connections type fusectl (rw,nosuid,nodev,noexec,relatime)
configfs on /sys/kernel/config type configfs (rw,nosuid,nodev,noexec,relatime)
none on /run/credentials/systemd-sysusers.service type ramfs (ro,nosuid,nodev,noexec,relatime,mode=700)
none on /run/credentials/systemd-tmpfiles-setup-dev.service type ramfs (ro,nosuid,nodev,noexec,relatime,mode=700)
none on /run/credentials/systemd-sysctl.service type ramfs (ro,nosuid,nodev,noexec,relatime,mode=700)
/dev/sdd2 on /boot/efi type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
none on /run/credentials/systemd-tmpfiles-setup.service type ramfs (ro,nosuid,nodev,noexec,relatime,mode=700)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,nosuid,nodev,noexec,relatime)
sunrpc on /run/rpc_pipefs type rpc_pipefs (rw,relatime)
lxcfs on /var/lib/lxcfs type fuse.lxcfs (rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other)
/dev/fuse on /etc/pve type fuse (rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other)
tmpfs on /run/user/0 type tmpfs (rw,nosuid,nodev,relatime,size=6576300k,nr_inodes=1644075,mode=700,inode64)
root@pve1:~#
root@pve1:~# cat /etc/fstab
# <file system> <mount point> <type> <options> <dump> <pass>
/dev/pve/root / ext4 errors=remount-ro 0 1
UUID=408D-F643 /boot/efi vfat defaults 0 1
/dev/pve/swap none swap sw 0 0
proc /proc proc defaults 0 0
root@pve1:~#
edit: forgot to answer this... ext4 and I think legacy boot though I can't remember for certain.