Igor Moiseev Applied mathematician, Web Developer

Surviving guide with Ceph and Proxmoxedit

After you've followed the familiar Proxmox Ceph Server manual youl'll have the brand new Ceph clutser up and running, here I'm collecting the basic tasks and command you'll need to manage Ceph cluster.

Ceph structure info

Disk structure

Ceph automatically configure and creates the block device in /dev/rbd/<pool-name>/

root@node1:~# ls -la /dev/rbd/<pool-name>/
total 0
drwxr-xr-x 2 root root 560 mar 26 15:05 .
drwxr-xr-x 3 root root  60 mar 23 13:29 ..
lrwxrwxrwx 1 root root  11 mar 26 12:39 vm-101-disk-1 -> ../../rbd0
lrwxrwxrwx 1 root root  11 mar 26 13:42 vm-102-disk-1 -> ../../rbd1
lrwxrwxrwx 1 root root  11 mar 23 19:34 vm-103-disk-1 -> ../../rbd2
lrwxrwxrwx 1 root root  11 mar 24 08:31 vm-103-disk-2 -> ../../rbd3

It is a normal block device that can be mounted in a regular way

root@node1:~# fdisk -l /dev/rbd0

Disk /dev/rbd0: 20 GiB, 21474836480 bytes, 41943040 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 4194304 bytes / 4194304 bytes
Disklabel type: dos
Disk identifier: 0x53332713

Device      Boot    Start      End  Sectors   Size Id Type
/dev/rbd0p1 *          63 41110334 41110272  19,6G 83 Linux
/dev/rbd0p2      41110335 41929649   819315 400,1M  5 Extended
/dev/rbd0p5      41110398 41913584   803187 392,2M 82 Linux swap

so

root@node1:~# mount /dev/rbd0p1 /media
root@node1:~# df -h
Filesystem                          Size  Used Avail Use% Mounted on
/dev/rbd0p1                          20G   17G  1,4G  93% /media
root@node1:~# ls -la /media/
total 2,1G
drwxr-xr-x  24 root root 4,0K mar 23 13:43 .
drwxr-xr-x  22 root root 4,0K mar  9 18:06 ..
drwxr-xr-x   2 root root 4,0K apr 10  2012 bin
drwxr-xr-x   3 root root 4,0K ago  8  2012 boot
lrwxrwxrwx   1 root root   11 apr  9  2010 cdrom -> media/cdrom
drwxr-xr-x   2 root root 4,0K set  3  2012 dev
drwxr-xr-x 109 root root  12K mar 23 13:43 etc
drwxr-xr-x  11 root root 4,0K mag 21  2013 home
drwxr-xr-x   2 root root 4,0K ott 26  2009 initrd
...

Config files structure

Benchmarking

BLOCK WRITE 4KB

root@node1:~# /usr/bin/rados -p rbd bench -b 4096 300 write -t 32 \
  --no-cleanup -m 10.0.4.1:6789 -n client.admin --keyring \
  /etc/pve/priv/ceph.client.admin.keyring --auth_supported cephx df

Total time run:         300.015640
Total writes made:      614977
Write size:             4096
Object size:            4096
Bandwidth (MB/sec):     8.0071
Stddev Bandwidth:       3.35268
Max bandwidth (MB/sec): 11.9766
Min bandwidth (MB/sec): 0.03125
Average IOPS:           2049
Stddev IOPS:            858
Max IOPS:               3066
Min IOPS:               8
Average Latency(s):     0.0156087
Stddev Latency(s):      0.0442384
Max latency(s):         1.51347
Min latency(s):         0.00396259