X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=pveceph.adoc;h=4132545f0ff9faa09c847c340faaf0e1c4363a66;hb=59b586cb297de3ef025910c6b8f9bf6375141b3e;hp=21a496560932e030fc31f84ce50d0f8427f6ba76;hpb=a474ca1f748336aaa3f1ee8991eb79452e726a9f;p=pve-docs.git

diff --git a/pveceph.adoc b/pveceph.adoc
index 21a4965..4132545 100644
--- a/pveceph.adoc
+++ b/pveceph.adoc
@@ -23,7 +23,7 @@ Manage Ceph Services on Proxmox VE Nodes
 :pve-toplevel:
 endif::manvolnum[]
 
-[thumbnail="gui-ceph-status.png"]
+[thumbnail="screenshot/gui-ceph-status.png"]
 
 {pve} unifies your compute and storage systems, i.e. you can use the same
 physical nodes within a cluster for both computing (processing VMs and
@@ -37,18 +37,16 @@ on the hypervisor nodes.
 Ceph is a distributed object store and file system designed to provide
 excellent performance, reliability and scalability.
 
-.Some of the advantages of Ceph are:
-- Easy setup and management with CLI and GUI support on Proxmox VE
+.Some advantages of Ceph on {pve} are:
+- Easy setup and management with CLI and GUI support
 - Thin provisioning
 - Snapshots support
 - Self healing
-- No single point of failure
 - Scalable to the exabyte level
 - Setup pools with different performance and redundancy characteristics
 - Data is replicated, making it fault tolerant
 - Runs on economical commodity hardware
 - No need for hardware RAID controllers
-- Easy management
 - Open source
 
 For small to mid sized deployments, it is possible to install a Ceph server for
@@ -83,10 +81,13 @@ Check also the recommendations from
 http://docs.ceph.com/docs/luminous/start/hardware-recommendations/[Ceph's website].
 
 .Avoid RAID
-While RAID controller are build for storage virtualisation, to combine
-independent disks to form one or more logical units. Their caching methods,
-algorithms (RAID modes; incl. JBOD), disk or write/read optimisations are
-targeted towards aforementioned logical units and not to Ceph.
+As Ceph handles data object redundancy and multiple parallel writes to disks
+(OSDs) on its own, using a RAID controller normally doesn’t improve
+performance or availability. On the contrary, Ceph is designed to handle whole
+disks on it's own, without any abstraction in between. RAID controller are not
+designed for the Ceph use case and may complicate things and sometimes even
+reduce performance, as their write and caching algorithms may interfere with
+the ones from Ceph.
 
 WARNING: Avoid RAID controller, use host bus adapter (HBA) instead.
 
@@ -108,7 +109,7 @@ This sets up an `apt` package repository in
 Creating initial Ceph configuration
 -----------------------------------
 
-[thumbnail="gui-ceph-config.png"]
+[thumbnail="screenshot/gui-ceph-config.png"]
 
 After installation of packages, you need to create an initial Ceph
 configuration on just one node, based on your network (`10.10.10.0/24`
@@ -130,7 +131,7 @@ Ceph commands without the need to specify a configuration file.
 Creating Ceph Monitors
 ----------------------
 
-[thumbnail="gui-ceph-monitor.png"]
+[thumbnail="screenshot/gui-ceph-monitor.png"]
 
 The Ceph Monitor (MON)
 footnote:[Ceph Monitor http://docs.ceph.com/docs/luminous/start/intro/]
@@ -173,7 +174,7 @@ pveceph createmgr
 Creating Ceph OSDs
 ------------------
 
-[thumbnail="gui-ceph-osd-status.png"]
+[thumbnail="screenshot/gui-ceph-osd-status.png"]
 
 via GUI or via CLI as follows:
 
@@ -277,7 +278,7 @@ highly recommended to achieve good performance.
 Creating Ceph Pools
 -------------------
 
-[thumbnail="gui-ceph-pools.png"]
+[thumbnail="screenshot/gui-ceph-pools.png"]
 
 A pool is a logical group for storing objects. It holds **P**lacement
 **G**roups (PG), a collection of objects.
@@ -394,7 +395,7 @@ separately.
 Ceph Client
 -----------
 
-[thumbnail="gui-ceph-log.png"]
+[thumbnail="screenshot/gui-ceph-log.png"]
 
 You can then configure {pve} to use such pools to store VM or
 Container images. Simply use the GUI too add a new `RBD` storage (see