From 64ac87bf2b5fc95ad33cff85cc72e4673db0e173 Mon Sep 17 00:00:00 2001 From: Zac Dover Date: Thu, 29 Jul 2021 00:37:46 +1000 Subject: [PATCH] doc/rados: rewrite storage device front matter This PR updates the text in the RADOS Guide (the Ceph Storage Cluster Guide) that appears at the beginning of the "Storage Devices" chapter. I did the following: - rewrote some of the sentences so that they read more like written text than like spoken language - added "Ceph Manager" to the list of daemons that a Ceph cluster comprises - that's about it. Signed-off-by: Zac Dover --- doc/rados/configuration/storage-devices.rst | 34 ++++++++++++--------- 1 file changed, 19 insertions(+), 15 deletions(-) diff --git a/doc/rados/configuration/storage-devices.rst b/doc/rados/configuration/storage-devices.rst index da679d4425d..139eeb1738b 100644 --- a/doc/rados/configuration/storage-devices.rst +++ b/doc/rados/configuration/storage-devices.rst @@ -2,22 +2,26 @@ Storage Devices ================= -There are two Ceph daemons that store data on devices: +There are several Ceph daemons in a storage cluster: -* **Ceph OSDs** (or Object Storage Daemons) are where most of the - data is stored in Ceph. Generally speaking, each OSD is backed by - a single storage device, like a traditional hard disk (HDD) or - solid state disk (SSD). OSDs can also be backed by a combination - of devices, like a HDD for most data and an SSD (or partition of an - SSD) for some metadata. The number of OSDs in a cluster is - generally a function of how much data will be stored, how big each - storage device will be, and the level and type of redundancy - (replication or erasure coding). -* **Ceph Monitor** daemons manage critical cluster state like cluster - membership and authentication information. For smaller clusters a - few gigabytes is all that is needed, although for larger clusters - the monitor database can reach tens or possibly hundreds of - gigabytes. +* **Ceph OSDs** (Object Storage Daemons) store most of the data + in Ceph. Usually each OSD is backed by a single storage device. + This can be a traditional hard disk (HDD) or a solid state disk + (SSD). OSDs can also be backed by a combination of devices: for + example, a HDD for most data and an SSD (or partition of an + SSD) for some metadata. The number of OSDs in a cluster is + usually a function of the amount of data to be stored, the size + of each storage device, and the level and type of redundancy + specified (replication or erasure coding). +* **Ceph Monitor** daemons manage critical cluster state. This + includes cluster membership and authentication information. + Small clusters require only a few gigabytes of storage to hold + the monitor database. In large clusters, however, the monitor + database can reach sizes of tens of gigabytes to hundreds of + gigabytes. +* **Ceph Manager** daemons run alongside monitor daemons, providing + additional monitoring and providing interfaces to external + monitoring and management systems. OSD Backends -- 2.39.5