Merge pull request #78981 from sr1kar99/1889-device-size-config

TELCODOCS#1889: Size info for LVMS

Author: jab-rh

modules/lvms-about-lvmcluster-cr.adoc

@@ -130,6 +130,24 @@ For example, if this field is set to 10, you can provision up to 10 times the am
 
 To disable over-provisioning, set this field to 1.
 
+|`thinPoolConfig.chunkSize`
+|`integer`
+|Specifies the statically calculated chunk size for the thin pool. This field is only used when the `ChunkSizeCalculationPolicy` field is set to `Static`. The value for this field must be configured in the range of 64 KiB to 1 GiB because of the underlying limitations of `lvm2`. 
+
+If you do not configure this field and the `ChunkSizeCalculationPolicy` field is set to `Static`, the default chunk size is set to 128 KiB.
+
+For more information, see "Overview of chunk size".
+
+|`thinPoolConfig.chunkSizeCalculationPolicy`
+|`string`
+|Specifies the policy to calculate the chunk size for the underlying volume group. You can set this field to either `Static` or `Host`. By default, this field is set to `Static`. 
+
+If this field is set to `Static`, the chunk size is set to the value of the `chunkSize` field. If the `chunkSize` field is not configured, chunk size is set to 128 KiB.
+
+If this field is set to `Host`, the chunk size is calculated based on the configuration in the `lvm.conf` file.
+
+For more information, see "Limitations to configure the size of the devices used in LVM Storage".
+
 |====
 
 

modules/lvms-limitations-to-configure-size-of-devices.adoc

@@ -5,7 +5,7 @@
 
 :_mod-docs-content-type: CONCEPT
 [id="limitations-to-configure-size-of-devices_{context}"]
-= Limitations to configure the size of the devices used in LVM Storage
+= Limitations to configure the size of the devices used in {lvms}
 
 The limitations to configure the size of the devices that you can use to provision storage using {lvms} are as follows:
 
@@ -23,36 +23,57 @@ ifdef::microshift[]
 endif::microshift[]
 
 ifndef::microshift[]
-.Size limits for different architectures using the default PE and LE size
-[cols="1,1,1,1,1", width="100%", options="header"]
+
+The following tables describe the chunk size and volume size limits for static and host configurations:
+
+.Tested configuration
+[cols="1,1", width="100%", options="header"]
+|====
+
+|Parameter
+|Value
+
+|Chunk size
+|128 KiB
+
+|Maximum volume size
+|32 TiB
+
+|====
+
+.Theoretical size limits for static configuration
+[cols="1,1,1", width="100%", options="header"]
+|====
+
+|Parameter
+|Minimum value
+|Maximum value
+
+|Chunk size
+|64 KiB
+|1 GiB
+
+|Volume size
+|Minimum size of the underlying {op-system-first} system.
+|Maximum size of the underlying {op-system} system.
+
 |====
-|Architecture
-|RHEL 6
-|RHEL 7
-|RHEL 8
-|RHEL 9
 
-|32-bit
-|16 TB
-|-
-|-
-|-
+.Theoretical size limits for a host configuration
+[cols="1,1", width="100%", options="header"]
+|====
 
-|64-bit
+|Parameter
+|Value
 
-|8 EB ^[1]^
+|Chunk size
+|This value is based on the configuration in the `lvm.conf` file. By default, this value is set to 128 KiB.
 
-100 TB ^[2]^
-|8 EB ^[1]^
+|Maximum volume size
+|Equal to the maximum volume size of the underlying {op-system} system.
 
-500 TB ^[2]^
-|8 EB
-|8 EB
+|Minimum volume size
+|Equal to the minimum volume size of the underlying {op-system} system.
 
 |====
-[.small]
---
-1. Theoretical size.
-2. Tested size.
---
-endif::microshift[]
+endif::microshift[]

snippets/lvms-creating-lvmcluster.adoc

@@ -37,5 +37,7 @@ spec:
         name: thin-pool-1
         sizePercent: 90 <1>
         overprovisionRatio: 10 
+        chunkSize: 128Ki <1>
+        chunkSizeCalculationPolicy: Static <1>
 ----
 <1> Optional field

storage/persistent_storage/persistent_storage_local/persistent-storage-using-lvms.adoc

@@ -47,22 +47,26 @@ include::modules/lvms-installing-logical-volume-manager-operator-using-rhacm.ado
 
 * xref:../../../storage/persistent_storage/persistent_storage_local/persistent-storage-using-lvms.adoc#about-lvmcluster_logical-volume-manager-storage[About the LVMCluster custom resource]
 
-// Limitations to configure the size of the devices to be used in LVM Storage
-include::modules/lvms-limitations-to-configure-size-of-devices.adoc[leveloffset=+1]
-
 // About the LVMCluster custom resource
 
 include::modules/lvms-about-lvmcluster-cr.adoc[leveloffset=+1]
 
 [role="_additional-resources"]
 .Additional resources
 
+* link:https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/9/html-single/configuring_and_managing_logical_volumes/index#overview-of-chunk-size_creating-and-managing-thin-provisioned-volumes[Overview of chunk size]
+
+* xref:../../../storage/persistent_storage/persistent_storage_local/persistent-storage-using-lvms.adoc#limitations-to-configure-size-of-devices_logical-volume-manager-storage[Limitations to configure the size of the devices used in {lvms}]
+
 * xref:../../../storage/persistent_storage/persistent_storage_local/persistent-storage-using-lvms.adoc#lvms-reusing-vg-from-prev-installation_logical-volume-manager-storage[Reusing a volume group from the previous LVM Storage installation]
 
 * xref:../../../storage/persistent_storage/persistent_storage_local/persistent-storage-using-lvms.adoc#about-adding-devices-to-a-vg_logical-volume-manager-storage[About adding devices to a volume group]
 
 * xref:../../../nodes/nodes/nodes-sno-worker-nodes.adoc[Adding worker nodes to {sno} clusters]
 
+// Limitations to configure the size of the devices to be used in LVM Storage
+include::modules/lvms-limitations-to-configure-size-of-devices.adoc[leveloffset=+2]
+
 // About adding devices to a volume group
 include::modules/lvms-about-adding-devices-to-a-vg.adoc[leveloffset=+2]