bump version to 6.2-5

[pve-docs.git] / pveceph.adoc

diff --git a/pveceph.adoc b/pveceph.adoc
index 8b86d62f596767f35ca8b8164cfcda5aa4bc8f11..baf0988dd93c788337ed2dab26d898b35a606b15 100644 (file)
--- a/pveceph.adoc
+++ b/pveceph.adoc
@@ -86,9 +86,16 @@ provide enough resources for stable and durable Ceph performance.
 .Memory
 Especially in a hyper-converged setup, the memory consumption needs to be
 carefully monitored. In addition to the intended workload from virtual machines
-and container, Ceph needs enough memory available to provide good and stable
-performance. As a rule of thumb, for roughly 1 TiB of data, 1 GiB of memory
-will be used by an OSD. OSD caching will use additional memory.
+and containers, Ceph needs enough memory available to provide excellent and
+stable performance.
+
+As a rule of thumb, for roughly **1 TiB of data, 1 GiB of memory** will be used
+by an OSD. Especially during recovery, rebalancing or backfilling.
+
+The daemon itself will use additional memory. The Bluestore backend of the
+daemon requires by default **3-5 GiB of memory** (adjustable). In contrast, the
+legacy Filestore backend uses the OS page cache and the memory consumption is
+generally related to PGs of an OSD daemon.
 
 .Network
 We recommend a network bandwidth of at least 10 GbE or more, which is used
@@ -101,7 +108,7 @@ services on the same network and may even break the {pve} cluster stack.
 
 Further, estimate your bandwidth needs. While one HDD might not saturate a 1 Gb
 link, multiple HDD OSDs per node can, and modern NVMe SSDs will even saturate
-10 Gbps of bandwidth quickly. Deploying a network capable of even more bandwith
+10 Gbps of bandwidth quickly. Deploying a network capable of even more bandwidth
 will ensure that it isn't your bottleneck and won't be anytime soon, 25, 40 or
 even 100 GBps are possible.
 
@@ -378,7 +385,7 @@ pveceph osd create /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)
+parameters respectively. If they are not given the following values (in order)
 will be used:
 
 * bluestore_block_{db,wal}_size from ceph configuration...
@@ -455,8 +462,9 @@ NOTE: The default number of PGs works for 2-5 disks. Ceph throws a
 
 It is advised to calculate the PG number depending on your setup, you can find
 the formula and the PG calculator footnote:[PG calculator
-https://ceph.com/pgcalc/] online. While PGs can be increased later on, they can
-never be decreased.
+https://ceph.com/pgcalc/] online. From Ceph Nautilus onwards it is possible to
+increase and decrease the number of PGs later on footnote:[Placement Groups
+https://docs.ceph.com/docs/{ceph_codename}/rados/operations/placement-groups/].
 
 
 You can create pools through command line or on the GUI on each PVE host under