In general SSDs will provide more IOPs than spinning disks. This fact and the
higher cost may make a xref:pve_ceph_device_classes[class based] separation of
pools appealing. Another possibility to speedup OSDs is to use a faster disk
-as journal or DB/WAL device, see xref:pve_ceph_osds[creating Ceph OSDs]. If a
-faster disk is used for multiple OSDs, a proper balance between OSD and WAL /
-DB (or journal) disk must be selected, otherwise the faster disk becomes the
-bottleneck for all linked OSDs.
+as journal or DB/**W**rite-**A**head-**L**og device, see
+xref:pve_ceph_osds[creating Ceph OSDs]. If a faster disk is used for multiple
+OSDs, a proper balance between OSD and WAL / DB (or journal) disk must be
+selected, otherwise the faster disk becomes the bottleneck for all linked OSDs.
Aside from the disk type, Ceph best performs with an even sized and distributed
amount of disks per node. For example, 4 x 500 GB disks with in each node is
among your, at least three nodes (4 OSDs on each node).
If the disk was used before (eg. ZFS/RAID/OSD), to remove partition table, boot
-sector and any OSD leftover the following commands should be sufficient.
+sector and any OSD leftover the following command should be sufficient.
[source,bash]
----
-dd if=/dev/zero of=/dev/sd[X] bs=1M count=200
-ceph-disk zap /dev/sd[X]
+ceph-volume lvm zap /dev/sd[X] --destroy
----
-WARNING: The above commands will destroy data on the disk!
+WARNING: The above command will destroy data on the disk!
Ceph Bluestore
~~~~~~~~~~~~~~
Starting with the Ceph Kraken release, a new Ceph OSD storage type was
introduced, the so called Bluestore
footnote:[Ceph Bluestore http://ceph.com/community/new-luminous-bluestore/].
-This is the default when creating OSDs in Ceph luminous.
+This is the default when creating OSDs since Ceph Luminous.
[source,bash]
----
pveceph createosd /dev/sd[X]
----
-NOTE: In order to select a disk in the GUI, to be more fail-safe, the disk needs
-to have a GPT footnoteref:[GPT, GPT partition table
-https://en.wikipedia.org/wiki/GUID_Partition_Table] partition table. You can
-create this with `gdisk /dev/sd(x)`. If there is no GPT, you cannot select the
-disk as DB/WAL.
+Block.db and block.wal
+^^^^^^^^^^^^^^^^^^^^^^
If you want to use a separate DB/WAL device for your OSDs, you can specify it
-through the '-journal_dev' option. The WAL is placed with the DB, if not
+through the '-db_dev' and '-wal_dev' options. The WAL is placed with the DB, if not
specified separately.
[source,bash]
----
-pveceph createosd /dev/sd[X] -journal_dev /dev/sd[Y]
+pveceph createosd /dev/sd[X] -db_dev /dev/sd[Y] -wal_dev /dev/sd[Z]
----
+You can directly choose the size for those with the '-db_size' and '-wal_size'
+paremeters respectively. If they are not given the following values (in order)
+will be used:
+
+* bluestore_block_{db,wal}_size from ceph configuration...
+** ... database, section 'osd'
+** ... database, section 'global'
+** ... file, section 'osd'
+** ... file, section 'global'
+* 10% (DB)/1% (WAL) of OSD size
+
NOTE: The DB stores BlueStore’s internal metadata and the WAL is BlueStore’s
internal journal or write-ahead log. It is recommended to use a fast SSD or
NVRAM for better performance.
Ceph Filestore
-~~~~~~~~~~~~~
-Till Ceph luminous, Filestore was used as storage type for Ceph OSDs. It can
-still be used and might give better performance in small setups, when backed by
-an NVMe SSD or similar.
-
-[source,bash]
-----
-pveceph createosd /dev/sd[X] -bluestore 0
-----
-
-NOTE: In order to select a disk in the GUI, the disk needs to have a
-GPT footnoteref:[GPT] partition table. You can
-create this with `gdisk /dev/sd(x)`. If there is no GPT, you cannot select the
-disk as journal. Currently the journal size is fixed to 5 GB.
-
-If you want to use a dedicated SSD journal disk:
-
-[source,bash]
-----
-pveceph createosd /dev/sd[X] -journal_dev /dev/sd[Y] -bluestore 0
-----
+~~~~~~~~~~~~~~
-Example: Use /dev/sdf as data disk (4TB) and /dev/sdb is the dedicated SSD
-journal disk.
+Before Ceph Luminous, Filestore was used as default storage type for Ceph OSDs.
+Starting with Ceph Nautilus, {pve} does not support creating such OSDs with
+'pveceph' anymore. If you still want to create filestore OSDs, use
+'ceph-volume' directly.
[source,bash]
----
-pveceph createosd /dev/sdf -journal_dev /dev/sdb -bluestore 0
+ceph-volume lvm create --filestore --data /dev/sd[X] --journal /dev/sd[Y]
----
-This partitions the disk (data and journal partition), creates
-filesystems and starts the OSD, afterwards it is running and fully
-functional.
-
-NOTE: This command refuses to initialize disk when it detects existing data. So
-if you want to overwrite a disk you should remove existing data first. You can
-do that using: 'ceph-disk zap /dev/sd[X]'
-
-You can create OSDs containing both journal and data partitions or you
-can place the journal on a dedicated SSD. Using a SSD journal disk is
-highly recommended to achieve good performance.
-
-
[[pve_ceph_pools]]
Creating Ceph Pools
-------------------
projects / pve-docs.git / blobdiff