Ceph rbd error - sysfs write failed

elurex

Active Member
Oct 28, 2015
204
15
38
Taiwan
I am running PVE 6.0 and on this pve node, I have already started 2 vm with rbd disks to my ceph storage, However, sometime if I need to start third VM using rbd disk, PVE will error with following msg. It only can be solve if I reboot the pve node and then I can start 3 VM or more using rbd disk

Code:
/dev/rbd6
/dev/rbd7
/dev/rbd8
rbd: sysfs write failed
can't unmap rbd device /dev/rbd/rbd/vm-104-disk-1: rbd: sysfs write failed
rbd: sysfs write failed
can't unmap rbd device /dev/rbd/rbd/vm-104-disk-2: rbd: sysfs write failed
rbd: sysfs write failed
can't unmap rbd device /dev/rbd/rbd/vm-104-disk-0: rbd: sysfs write failed
TASK ERROR: start failed: command '/usr/bin/kvm -id 104 -name winclient104 -chardev 'socket,id=qmp,path=/var/run/qemu-server/104.qmp,server,nowait' -mon 'chardev=qmp,mode=control' -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' -mon 'chardev=qmp-event,mode=control' -pidfile /var/run/qemu-server/104.pid -daemonize -smbios 'type=1,uuid=b9595b11-142c-41b5-bba9-25f359770a91' -drive 'if=pflash,unit=0,format=raw,readonly,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' -drive 'if=pflash,unit=1,format=raw,id=drive-efidisk0,file=/dev/rbd/rbd/vm-104-disk-0' -smp '8,sockets=1,cores=8,maxcpus=8' -nodefaults -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' -vga none -nographic -no-hpet -cpu 'host,+kvm_pv_unhalt,+kvm_pv_eoi,hv_vendor_id=proxmox,hv_spinlocks=0x1fff,hv_vapic,hv_time,hv_reset,hv_vpindex,hv_runtime,hv_relaxed,hv_synic,hv_stimer,hv_ipi,kvm=off' -m 16384 -object 'memory-backend-ram,id=ram-node0,size=16384M' -numa 'node,nodeid=0,cpus=0-7,memdev=ram-node0' -readconfig /usr/share/qemu-server/pve-q35.cfg -device 'usb-tablet,id=tablet,bus=ehci.0,port=1' -device 'vfio-pci,host=b2:00.0,id=hostpci0.0,bus=ich9-pcie-port-1,addr=0x0.0,multifunction=on' -device 'vfio-pci,host=b2:00.1,id=hostpci0.1,bus=ich9-pcie-port-1,addr=0x0.1' -device 'vfio-pci,host=b2:00.2,id=hostpci0.2,bus=ich9-pcie-port-1,addr=0x0.2' -device 'vfio-pci,host=b2:00.3,id=hostpci0.3,bus=ich9-pcie-port-1,addr=0x0.3' -chardev 'socket,path=/var/run/qemu-server/104.qga,server,nowait,id=qga0' -device 'virtio-serial,id=qga0,bus=pci.0,addr=0x8' -device 'virtserialport,chardev=qga0,name=org.qemu.guest_agent.0' -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' -iscsi 'initiator-name=iqn.1993-08.org.debian:01:cb85eb190f0' -device 'virtio-scsi-pci,id=scsihw0,bus=pci.0,addr=0x5' -drive 'file=/dev/rbd/rbd/vm-104-disk-1,if=none,id=drive-scsi0,cache=writeback,discard=on,throttling.bps-read=419430400,throttling.iops-read=8000,throttling.bps-write=419430400,throttling.iops-write=8000,format=raw,aio=threads,detect-zeroes=unmap' -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100' -drive 'file=/dev/rbd/rbd/vm-104-disk-2,if=none,id=drive-scsi1,cache=writeback,discard=on,throttling.bps-read=419430400,throttling.iops-read=8000,throttling.bps-write=419430400,throttling.iops-write=8000,format=raw,aio=threads,detect-zeroes=unmap' -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=1,drive=drive-scsi1,id=scsi1' -netdev 'type=tap,id=net0,ifname=tap104i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' -device 'virtio-net-pci,mac=3A:C2:94:31:A4:C4,netdev=net0,bus=pci.0,addr=0x12,id=net0' -rtc 'driftfix=slew,base=localtime' -machine 'type=pc-q35-3.1' -global 'kvm-pit.lost_tick_policy=discard'' failed: got timeout

Code:
rbd image 'vm-104-disk-1':
        size 60 GiB in 15360 objects
        order 22 (4 MiB objects)
        snapshot_count: 0
        id: 433efbc6fb9b03
        block_name_prefix: rbd_data.433efbc6fb9b03
        format: 2
        features: layering
        op_features:
        flags:
        create_timestamp: Fri Sep  6 01:24:48 2019
        access_timestamp: Fri Sep  6 01:24:48 2019
        modify_timestamp: Fri Sep  6 01:24:48 2019

root@gpu01:~# rados -p rbd listwatchers rbd_data.433efbc6fb9b03
error listing watchers rbd/rbd_data.433efbc6fb9b03: (2) No such file or directory

root@gpu01:~# rbd status -p rbd vm-104-disk-1
Watchers: none

root@gpu01:~# rbd showmapped
id pool namespace image         snap device
0  rbd            vm-101-disk-1 -    /dev/rbd0
1  rbd            vm-101-disk-2 -    /dev/rbd1
2  rbd            vm-101-disk-0 -    /dev/rbd2
3  rbd            vm-102-disk-1 -    /dev/rbd3
4  rbd            vm-102-disk-2 -    /dev/rbd4
5  rbd            vm-102-disk-0 -    /dev/rbd5

root@gpu01:~#  ceph health detail
HEALTH_OK

There is no other rbd client open that image

# pveversion -v
proxmox-ve: 6.0-2 (running kernel: 5.0.21-2-pve)
pve-manager: 6.0-7 (running version: 6.0-7/28984024)
pve-kernel-5.0: 6.0-8
pve-kernel-helper: 6.0-8
pve-kernel-5.0.21-2-pve: 5.0.21-3
pve-kernel-5.0.21-1-pve: 5.0.21-2
pve-kernel-5.0.15-1-pve: 5.0.15-1
ceph: 14.2.2-pve1
ceph-fuse: 14.2.2-pve1
corosync: 3.0.2-pve2
criu: 3.11-3
glusterfs-client: 5.5-3
ksm-control-daemon: 1.3-1
libjs-extjs: 6.0.1-10
libknet1: 1.12-pve1
libpve-access-control: 6.0-2
libpve-apiclient-perl: 3.0-2
libpve-common-perl: 6.0-4
libpve-guest-common-perl: 3.0-1
libpve-http-server-perl: 3.0-2
libpve-storage-perl: 6.0-8
libqb0: 1.0.5-1
lvm2: 2.03.02-pve3
lxc-pve: 3.1.0-65
lxcfs: 3.0.3-pve60
novnc-pve: 1.0.0-60
proxmox-mini-journalreader: 1.1-1
proxmox-widget-toolkit: 2.0-7
pve-cluster: 6.0-7
pve-container: 3.0-7
pve-docs: 6.0-4
pve-edk2-firmware: 2.20190614-1
pve-firewall: 4.0-7
pve-firmware: 3.0-2
pve-ha-manager: 3.0-2
pve-i18n: 2.0-3
pve-qemu-kvm: 4.0.0-5
pve-xtermjs: 3.13.2-1
qemu-server: 6.0-7
smartmontools: 7.0-pve2
spiceterm: 3.1-1
vncterm: 1.6-1
zfsutils-linux: 0.8.1-pve2
 
Last edited:
I am running PVE 6.0 and on this pve node,
IS this a client or part of a Ceph cluster? If part of PVE + Ceph cluster, can you please post a ceph versions?

root@gpu01:~# rados -p rbd listwatchers rbd_data.433efbc6fb9b03 error listing watchers rbd/rbd_data.433efbc6fb9b03: (2) No such file or directory

rbd: sysfs write failed can't unmap rbd device /dev/rbd/rbd/vm-104-disk-1: rbd: sysfs write failed
Is there anything in the logs (journal/syslog, ceph)?
 
Code:
root@gpu01:~# ceph versions
{
    "mon": {
        "ceph version 14.2.2 (a887fe9a5d3d97fe349065d3c1c9dbd7b8870855) nautilus (stable)": 3
    },
    "mgr": {
        "ceph version 14.2.2 (a887fe9a5d3d97fe349065d3c1c9dbd7b8870855) nautilus (stable)": 1
    },
    "osd": {
        "ceph version 14.2.2 (a887fe9a5d3d97fe349065d3c1c9dbd7b8870855) nautilus (stable)": 96
    },
    "mds": {},
    "overall": {
        "ceph version 14.2.2 (a887fe9a5d3d97fe349065d3c1c9dbd7b8870855) nautilus (stable)": 100
    }
}

syslog

Code:
root@gpu01:/var/log# cat syslog.1|grep rbd|grep unmap
Oct  2 20:37:38 gpu01-la3 pvedaemon[3351852]: can't unmap rbd device /dev/rbd/rbd/vm-103-disk-1: rbd: sysfs write failed
Oct  2 20:37:38 gpu01-la3 pvedaemon[3351852]: can't unmap rbd device /dev/rbd/rbd/vm-103-disk-2: rbd: sysfs write failed
Oct  2 20:37:39 gpu01-la3 pvedaemon[3351852]: can't unmap rbd device /dev/rbd/rbd/vm-103-disk-0: rbd: sysfs write failed
Oct  2 20:37:39 gpu01-la3 pvedaemon[3351852]: start failed: command '/usr/bin/kvm -id 103 -name winclient103 -chardev 'socket,id=qmp,path=/var/run/qemu-server/103.qmp,server,nowait' -mon 'chardev=qmp,mode=control' -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' -mon 'chardev=qmp-event,mode=control' -pidfile /var/run/qemu-server/103.pid -daemonize -smbios 'type=1,uuid=e5190607-223f-4886-a9eb-1650123a9b66' -drive 'if=pflash,unit=0,format=raw,readonly,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' -drive 'if=pflash,unit=1,format=raw,id=drive-efidisk0,file=/dev/rbd/rbd/vm-103-disk-0' -smp '8,sockets=1,cores=8,maxcpus=8' -nodefaults -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' -vga none -nographic -no-hpet -cpu 'host,+kvm_pv_unhalt,+kvm_pv_eoi,hv_vendor_id=proxmox,hv_spinlocks=0x1fff,hv_vapic,hv_time,hv_reset,hv_vpindex,hv_runtime,hv_relaxed,hv_synic,hv_stimer,hv_ipi,kvm=off' -m 16384 -object 'memory-backend-ram,id=ram-node0,size=16384M' -numa 'node,nodeid=0,cpus=0-7,memdev=ram-node0' -readconfig /usr/share/qemu-server/pve-q35.cfg -device 'usb-tablet,id=tablet,bus=ehci.0,port=1' -device 'vfio-pci,host=b2:00.0,id=hostpci0.0,bus=ich9-pcie-port-1,addr=0x0.0,multifunction=on' -device 'vfio-pci,host=b2:00.1,id=hostpci0.1,bus=ich9-pcie-port-1,addr=0x0.1' -device 'vfio-pci,host=b2:00.2,id=hostpci0.2,bus=ich9-pcie-port-1,addr=0x0.2' -device 'vfio-pci,host=b2:00.3,id=hostpci0.3,bus=ich9-pcie-port-1,addr=0x0.3' -chardev 'socket,path=/var/run/qemu-server/103.qga,server,nowait,id=qga0' -device 'virtio-serial,id=qga0,bus=pci.0,addr=0x8' -device 'virtserialport,chardev=qga0,name=org.qemu.guest_agent.0' -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' -iscsi 'initiator-name=iqn.1993-08.org.debian:01:cb85eb190f0' -device 'virtio-scsi-pci,id=scsihw0,bus=pci.0,addr=0x5' -drive 'file=/dev/rbd/rbd/vm-103-disk-1,if=none,id=drive-scsi0,cache=writeback,discard=on,throttling.bps-read=419430400,throttling.iops-read=8000,throttling.bps-write=419430400,throttling.iops-write=8000,format=raw,aio=threads,detect-zeroes=unmap' -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100' -drive 'file=/dev/rbd/rbd/vm-103-disk-2,if=none,id=drive-scsi1,cache=writeback,discard=on,throttling.bps-read=419430400,throttling.iops-read=8000,throttling.bps-write=419430400,throttling.iops-write=8000,format=raw,aio=threads,detect-zeroes=unmap' -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=1,drive=drive-scsi1,id=scsi1' -netdev 'type=tap,id=net0,ifname=tap103i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' -device 'virtio-net-pci,mac=3A:C2:94:31:A4:C4,netdev=net0,bus=pci.0,addr=0x12,id=net0' -rtc 'driftfix=sle
w,base=localtime' -machine 'type=pc-q35-3.1' -global 'kvm-pit.lost_tick_policy=discard'' failed: got timeout
Oct  2 20:37:39 gpu01-la3 pvedaemon[508130]: <mquery@pam> end task UPID:gpu01:0033252C:0467553A:5D956CE3:qmstart:103:mquery@pam: start failed: command '/usr/bin/kvm -id 103 -name winclient103 -chardev 'socket,id=qmp,path=/var/run/qemu-server/103.qmp,server,nowait' -mon 'chardev=qmp,mode=control' -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' -mon 'chardev=qmp-event,mode=control' -pidfile /var/run/qemu-server/103.pid -daemonize -smbios 'type=1,uuid=e5190607-223f-4886-a9eb-1650123a9b66' -drive 'if=pflash,unit=0,format=raw,readonly,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' -drive 'if=pflash,unit=1,format=raw,id=drive-efidisk0,file=/dev/rbd/rbd/vm-103-disk-0' -smp '8,sockets=1,cores=8,maxcpus=8' -nodefaults -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' -vga none -nographic -no-hpet -cpu 'host,+kvm_pv_unhalt,+kvm_pv_eoi,hv_vendor_id=proxmox,hv_spinlocks=0x1fff,hv_vapic,hv_time,hv_reset,hv_vpindex,hv_runtime,hv_relaxed,hv_synic,hv_stimer,hv_ipi,kvm=off' -m 16384 -object 'memory-backend-ram,id=ram-node0,size=16384M' -numa 'node,nodeid=0,cpus=0-7,memdev=ram-node0' -readconfig /usr/share/qemu-server/pve-q35.cfg -device 'usb-tablet,id=tablet,bus=ehci.0,port=1' -device 'vfio-pci,host=b2:00.0,id=hostpci0.0,bus=ich9-pcie-port-1,addr=0x0.0,multifunction=on' -device 'vfio-pci,host=b2:00.1,id=hostpci0.1,bus=ich9-pcie-port-1,addr=0x0.1' -device 'vfio-pci,host=b2:00.2,id=hostpci0.2,bus=ich9-pcie-port-1,addr=0x0.2' -device 'vfio-pci,host=b2:00.3,id=hostpci0.3,bus=ich9-pcie-port-1,addr=0x0.3' -chardev 'socket,path=/var/run/qemu-server/103.qga,server,nowait,id=qga0' -device 'virtio-serial,id=qga0,bus=pci.0,addr=0x8' -device 'virtserialport,chardev=qga0,name=org.qemu.guest_agent.0' -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' -iscsi 'initiator-name=iqn.1993-08.org.debian:01:cb85eb190f0' -device 'virtio-scsi-pci,id=scsihw0,bus=pci.0,addr=0x5' -drive 'file=/dev/rbd/rbd/vm-103-disk-1,if=none,id=drive-scsi0,cache=writeback,discard=on,throttling.bps-read=419430400,throttling.iops-read=8000,throttling.bps-write=419430400,throttling.iops-write=8000,format=raw,aio=threads,detect-zeroes=unmap' -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100' -drive 'file=/dev/rbd/rbd/vm-103-disk-2,if=none,id=drive-scsi1,cache=writeback,discard=on,throttling.bps-read=419430400,throttling.iops-read=8000,throttling.bps-write=419430400,throttling.iops-write=8000,format=raw,aio=threads,detect-zeroes=unmap' -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=1,drive=drive-scsi1,id=scsi1' -netdev 'type=tap,id=net0,ifname=tap103i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' -device 'virtio-net-pc
i,mac=3A:C2:94:31:A4:C4,netdev=net0,bus=pci.0,addr=0x12,id=net0' -rtc 'driftfix=slew,base=localtime' -machine 'type=pc-q35-3.1' -global 'kvm-pit.lost_tick_policy=discard'' failed: got timeout

Nothing on the ceph log
 
Code:
rbd image 'vm-104-disk-1':
        size 60 GiB in 15360 objects
        order 22 (4 MiB objects)
        snapshot_count: 0
        id: 433efbc6fb9b03
        block_name_prefix: rbd_data.433efbc6fb9b03
        format: 2
        features: layering
        op_features:
        flags:
        create_timestamp: Fri Sep  6 01:24:48 2019
        access_timestamp: Fri Sep  6 01:24:48 2019
        modify_timestamp: Fri Sep  6 01:24:48 2019

provided in first post


also, what is the result of

#rbd info rbd/vm-104-disk-1
 
currently proxmox disable some features

/usr/share/perl5/PVE/Storage/RBDPlugin.pm

my $krbd_feature_blacklist = ['deep-flatten', 'fast-diff', 'object-map', 'exclusive-lock'];

This was for old kernel on proxmox5, but this has not been updated.

I'm thinking about exclusive-lock (since kernel 4.10), maybe it could help in your case.

#rbd feature enable rbd/vm-104-disk-1 exclusive-lock
 
.....

#rbd feature enable rbd/vm-104-disk-1 exclusive-lock

Does not work
........
root@gpu05:~# rbd feature enable rbd/vm-104-disk-0 exclusive-lock
root@gpu05:~# rbd feature enable rbd/vm-104-disk-1 exclusive-lock
root@gpu05:~# rbd feature enable rbd/vm-104-disk-2 exclusive-lock

1570504539728.png

Code:
/dev/rbd9
/dev/rbd10
/dev/rbd11
rbd: sysfs write failed
can't unmap rbd device /dev/rbd/rbd/vm-104-disk-1: rbd: sysfs write failed
rbd: sysfs write failed
can't unmap rbd device /dev/rbd/rbd/vm-104-disk-2: rbd: sysfs write failed
rbd: sysfs write failed
can't unmap rbd device /dev/rbd/rbd/vm-104-disk-0: rbd: sysfs write failed
TASK ERROR: start failed: command '/usr/bin/kvm -id 104 -name winclient104 -chardev 'socket,id=qmp,path=/var/run/qemu-server/104.qmp,server,nowait' -mon 'chardev=qmp,mode=control' -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' -mon 'chardev=qmp-event,mode=control' -pidfile /var/run/qemu-server/104.pid -daemonize -smbios 'type=1,uuid=b9595b11-142c-41b5-bba9-25f359770a91' -drive 'if=pflash,unit=0,format=raw,readonly,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' -drive 'if=pflash,unit=1,format=raw,id=drive-efidisk0,file=/dev/rbd/rbd/vm-104-disk-0' -smp '8,sockets=1,cores=8,maxcpus=8' -nodefaults -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' -vga none -nographic -no-hpet -cpu 'host,+kvm_pv_unhalt,+kvm_pv_eoi,hv_vendor_id=proxmox,hv_spinlocks=0x1fff,hv_vapic,hv_time,hv_reset,hv_vpindex,hv_runtime,hv_relaxed,hv_synic,hv_stimer,hv_ipi,kvm=off' -m 16384 -object 'memory-backend-ram,id=ram-node0,size=16384M' -numa 'node,nodeid=0,cpus=0-7,memdev=ram-node0' -readconfig /usr/share/qemu-server/pve-q35.cfg -device 'usb-tablet,id=tablet,bus=ehci.0,port=1' -device 'vfio-pci,host=3e:00.0,id=hostpci0.0,bus=ich9-pcie-port-1,addr=0x0.0,multifunction=on' -device 'vfio-pci,host=3e:00.1,id=hostpci0.1,bus=ich9-pcie-port-1,addr=0x0.1' -device 'vfio-pci,host=3e:00.2,id=hostpci0.2,bus=ich9-pcie-port-1,addr=0x0.2' -device 'vfio-pci,host=3e:00.3,id=hostpci0.3,bus=ich9-pcie-port-1,addr=0x0.3' -chardev 'socket,path=/var/run/qemu-server/104.qga,server,nowait,id=qga0' -device 'virtio-serial,id=qga0,bus=pci.0,addr=0x8' -device 'virtserialport,chardev=qga0,name=org.qemu.guest_agent.0' -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' -iscsi 'initiator-name=iqn.1993-08.org.debian:01:cb85eb190f0' -device 'virtio-scsi-pci,id=scsihw0,bus=pci.0,addr=0x5' -drive 'file=/dev/rbd/rbd/vm-104-disk-1,if=none,id=drive-scsi0,cache=writeback,discard=on,throttling.bps-read=419430400,throttling.iops-read=8000,throttling.bps-write=419430400,throttling.iops-write=8000,format=raw,aio=threads,detect-zeroes=unmap' -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100' -drive 'file=/dev/rbd/rbd/vm-104-disk-2,if=none,id=drive-scsi1,cache=writeback,discard=on,throttling.bps-read=419430400,throttling.iops-read=8000,throttling.bps-write=419430400,throttling.iops-write=8000,format=raw,aio=threads,detect-zeroes=unmap' -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=1,drive=drive-scsi1,id=scsi1' -netdev 'type=tap,id=net0,ifname=tap104i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' -device 'virtio-net-pci,mac=86:FE:6B:F7:96:F4,netdev=net0,bus=pci.0,addr=0x12,id=net0' -rtc 'driftfix=slew,base=localtime' -machine 'type=pc-q35-3.1' -global 'kvm-pit.lost_tick_policy=discard'' failed: got timeout
 
Code:
root@gpu01:~# rbd showmapped
id pool namespace image         snap device
0  rbd            vm-101-disk-1 -    /dev/rbd0
1  rbd            vm-101-disk-2 -    /dev/rbd1
2  rbd            vm-101-disk-0 -    /dev/rbd2
3  rbd            vm-104-disk-1 -    /dev/rbd3
4  rbd            vm-104-disk-2 -    /dev/rbd4
5  rbd            vm-104-disk-0 -    /dev/rbd5
6  rbd            vm-102-disk-1 -    /dev/rbd6
7  rbd            vm-102-disk-2 -    /dev/rbd7
8  rbd            vm-102-disk-0 -    /dev/rbd8

root@gpu01:~# rbd map rbd/vm-103-disk-2
/dev/rbd9

root@gpu01:~# rbd unmap rbd/vm-103-disk-2

This is strange because doing via cli it all works, but when pve trying to start a vm with RBD disk, it will error
 
no, I don't....

Code:
root@gpu01:/etc/pve/priv/ceph# ls -al
total 0
drwx------ 2 root www-data 0 Aug 12 05:10 .
drwx------ 2 root www-data 0 May  3 05:02 ..

A temporarily work around this issue is to reboot pve host,
then it will stop working again mounting additional rbd disk with sysfs write error after sometimes