fix wiki-special link to "USB installation"

[pve-docs.git] / pveceph.adoc

diff --git a/pveceph.adoc b/pveceph.adoc
index 8b86d62f596767f35ca8b8164cfcda5aa4bc8f11..8dc85680ded076094afd9d7afb724f5ccd1761e7 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
 .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
 
 .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
 
 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.
 
 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'
 ----
 
 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...
 will be used:
 
 * bluestore_block_{db,wal}_size from ceph configuration...