[LOS-597] document what content is served from /mnt/data3

docs/distributions/architecture.md

@@ -19,10 +19,21 @@ The following symlinks exist, linked to the above git repository.
 
 | Mount path | Purpose
 | -- | -- |
-| /mnt/data2 | Staging area |
-| /mnt/data1 | Production area |
+| /mnt/data2 | Staging area (cephfs) |
+| /mnt/data1 | Production area (cephfs) |
+| /mnt/data3 | Production area (flash cephfs) |
 | /eos/project	| Archive area |
 
+## /mnt/data3
+* The flash cephfs storage (/mnt/data3) has limited quota, however is much faster than the standard cephfs cluster. For this reason we host the most actively used content from this location.
+* To avoid channging urls for content, we use symlinks from /mnt/data1 (which is the DocumentRoot for linuxsoft.cern.ch) to /mnt/data3. This is documented as follows:
+
+| /mnt/data1 Path | /mnt/data3 Path | Content
+| -- | -- | --- |
+| /mnt/data1/dist/centos | /mnt/data3/centos | Upstream CentOS repository |
+| /mnt/data1/dist/cern/centos | /mnt/data3/cern/centos | CERN CentOS |
+| /mnt/data1/dist/internal/repos | /mnt/data3/internal/repos | Koji repos |
+
 ## lxsoft update hosts
 
 these hosts are used to confirm that released rpms from testing/production are safe
@@ -45,6 +56,11 @@ In addition, for testing purposes we also have 2 RHEL hosts which an be rebuilt
 | lxvmrh7t-amd64 | RedHat Enterprise Linux 7 (RHEL7) x86_64 | "Testing" RHEL7 VM |
 | lxvmrh8t-amd64 | RedHat Enterprise Linux 8 (RHEL8) x86_64 | "Testing" RHEL8 VM |
 
+A C8 node is also available
+
+| fqdn | dist/arch | function
+| -- | -- | --- |
+| lxvmc8t-amd64 | CentOS 8 x86_64 | "Testing" C8 VM |
 
 * The rebuild process is scripted via AIMS. Essentially these VMs have an iPXE image defined as their boot image so to rebuild we set the AIMS pxeon flag and issue an 'openstack server rebuild' command to the VM in question.