diff --git a/docs/20_Checks/_index.md b/docs/20_Checks/_index.md
index e6a5a9976937ba507c6ce0c5ca1280c14fa40b68..f4620728d62b895015dfeee943320378eaf43744 100644
--- a/docs/20_Checks/_index.md
+++ b/docs/20_Checks/_index.md
@@ -9,7 +9,8 @@ There is one include script used by all checks:
 
 * [check_apache_requests](check_apache_requests.md)
 * check_backup_one
-* check_ceph_diskfree
+* [check_ceph_diskfree](check_ceph_diskfree.md)
+* [check_ceph_io](check_ceph_io.md)
 * check_ceph_osd
 * check_ceph_status
 * check_clientbackup
@@ -33,7 +34,7 @@ There is one include script used by all checks:
 * check_sensuplugins
 * check_smartstatus
 * [check_snmp_data](check_snmp_data.md)
-* check_snmp_synology
+* [check_snmp_synology](check_snmp_synology.md)
 * check_ssl
 * check_systemdservices
 * check_timesync
diff --git a/docs/20_Checks/check_ceph_diskfree.md b/docs/20_Checks/check_ceph_diskfree.md
new file mode 100644
index 0000000000000000000000000000000000000000..3a96e2491adeca37170d1f7d16b178d79c9e6250
--- /dev/null
+++ b/docs/20_Checks/check_ceph_diskfree.md
@@ -0,0 +1,60 @@
+# check Ceph diskfree
+
+## Introduction
+
+**check_cehp_diskfree** is a plugin to show the available and free diskspace.
+It returns a single line for the status, data and performance data.
+
+## Requirements
+
+* `ceph` binary and sudo permission on it to get the information
+
+## Syntax
+
+```
+$ check_ceph_diskfree -h
+______________________________________________________________________
+
+CHECK_CEPH_DISKFREE 
+v1.3
+
+(c) Institute for Medical Education - University of Bern
+Licence: GNU GPL 3
+______________________________________________________________________
+
+Show available and free space on a ceph cluster.
+This check sends performance data.
+
+It uses 'ceph df' to parse data.
+
+SYNTAX:
+check_ceph_diskfree
+
+OPTIONS:
+    -h or --help   show this help.
+```
+
+### Parameters
+
+(none)
+
+## Examples
+
+`$ check_ceph_diskfree` returns
+
+```txt
+check_ceph_diskfree 
+OK: Disksize on Ceph cluster and its pools - warnings: 0 (70 %) .. critcal: 0 (90 %)
+
+           --- RAW STORAGE ---
+           CLASS    SIZE   AVAIL     USED  RAW USED  %RAW USED
+OK         ssd    54 TiB  53 TiB  767 GiB   767 GiB       1.40
+OK         TOTAL  54 TiB  53 TiB  767 GiB   767 GiB       1.40
+
+           --- POOLS ---
+           POOL  ID  PGS   STORED  OBJECTS     USED  %USED  MAX AVAIL
+OK         .mgr   1    1   18 MiB        6   18 MiB      0     16 TiB
+OK         one    2   32  255 GiB   66.65k  255 GiB   0.50     16 TiB
+OK         two    3   32      0 B        0      0 B      0     25 TiB
+ |global-total=59373627899904;;;0;59373627899904 global-avail=58274116272128;;;0;59373627899904 global-used=823559979008;;;0;59373627899904 
+...
diff --git a/docs/20_Checks/check_ceph_io.md b/docs/20_Checks/check_ceph_io.md
new file mode 100644
index 0000000000000000000000000000000000000000..8a0c10d228cfeb9cfff7e1ce8c7b8be742dfb947
--- /dev/null
+++ b/docs/20_Checks/check_ceph_io.md
@@ -0,0 +1,46 @@
+# check Ceph IO
+
+## Introduction
+
+**check_cehp_io** is a plugin to show read and written bytes per second. 
+It returns a single line for the status and performance data.
+
+## Requirements
+
+* `ceph` binary and sudo permission on it to get the information
+
+## Syntax
+
+```
+$ check_ceph_io --help
+______________________________________________________________________
+
+CHECK_CEPH_IO 
+v1.0
+
+(c) Institute for Medical Education - University of Bern
+Licence: GNU GPL 3
+______________________________________________________________________
+
+Show cheph IO as read and written bytes per second.
+This check sends performance data.
+
+SYNTAX:
+check_ceph_io
+
+OPTIONS:
+    -h or --help   show this help.
+```
+
+### Parameters
+
+(none)
+
+## Examples
+
+`$ check_ceph_io` returns
+
+```txt
+OK:    13 KiB/s rd, 1.1 MiB/s wr, 130 op/s rd, 137 op/s wr
+|cephio-read=13K;; cephio-write=1.1M;;
+...
diff --git a/docs/20_Checks/check_eol.md b/docs/20_Checks/check_eol.md
index 9c2173683357f7d7a970ad87bedae7d9035d0d6b..ed065393371a84f3bda07de95de3d8185b5c4370 100644
--- a/docs/20_Checks/check_eol.md
+++ b/docs/20_Checks/check_eol.md
@@ -133,24 +133,28 @@ Al other lines, like empty lines, lines starting with special characters are ign
 
 Snippet:
 
-    # --------------------------------------------
-    centos:The CentOS Project
-    centos:website https://www.centos.org/
-    # --------------------------------------------
-
-    centos:6:2020-11-30
-    centos:7:2024-06-30
-    centos:8:2029-05-31
+```txt
+# --------------------------------------------
+centos:The CentOS Project
+centos:website https://www.centos.org/
+# --------------------------------------------
+
+centos:6:2020-11-30
+centos:7:2024-06-30
+centos:8:2029-05-31
+```
 
 Example output:
 
-    $ check_eol centos 7
-    OK [centos 7] ends on 2024-06-30 ... 1586 days left 
+```txt
+$ check_eol centos 7
+OK [centos 7] ends on 2024-06-30 ... 1586 days left 
 
-    The CentOS Project
-    website https://www.centos.org/
+The CentOS Project
+website https://www.centos.org/
 
-    Limit Info: warn below 365 days; critical below 90 days
+Limit Info: warn below 365 days; critical below 90 days
+```
 
 #### Files
 
diff --git a/docs/20_Checks/check_snmp_data.md b/docs/20_Checks/check_snmp_data.md
index 8a182e40d101aab25694354d94eebbe11bbf7e82..27bbc2e9d7df99f237aa94fc88762d372583efa2 100644
--- a/docs/20_Checks/check_snmp_data.md
+++ b/docs/20_Checks/check_snmp_data.md
@@ -113,3 +113,20 @@ To fetch configuration data the text in $0 is grepped by `^# DATA:`.
 There is a single line with **label** to define a short description of the check.
 
 There can be severeal lines with **data** to define the values to get. Each data line must have a uniq label within the same check.
+
+## SNMP authentication configuration
+
+In a configuration file you can put the authentication parameters for snmpget and snmpwalk.
+
+By default it reads /etc/icinga2/snmp.cfg - but you can use `-f FILENAME` to override it.
+
+```txt
+sudo cat /etc/icinga2/snmp.cfg 
+#
+# snmp-connections
+# SYNTAX: [hostname]:[params]
+#
+DEFAULT:-v 2c -c public
+server-01.example.com:-v 3 -l authnoPriv -a SHA -u imlmonitor -A password-for-server-01
+server-02.example.com:-v 3 -l authnoPriv -a SHA -u imlmonitor -A password-for-server-02
+```
diff --git a/docs/20_Checks/check_snmp_synology.md b/docs/20_Checks/check_snmp_synology.md
new file mode 100644
index 0000000000000000000000000000000000000000..b53123315bd679c75aa18cb4ff03211d0b95c275
--- /dev/null
+++ b/docs/20_Checks/check_snmp_synology.md
@@ -0,0 +1,168 @@
+# check SNMP Synology
+
+## Introduction
+
+**check_snmp_data** is a plugin to check the status of a Synology storage using snmp v2 or v3.
+
+## Syntax
+
+Start the script without parameter to get the help.
+
+```txt
+______________________________________________________________________
+
+CHECK_SNMP_SYNOLOGY 
+v1.2
+
+Based on script of Nicolas Ordonez.
+
+Institute for Medical Education - University of Bern
+Licence: GNU GPL 3
+______________________________________________________________________
+
+Check health of a Synology drive using SNMP.
+
+SYNTAX:
+    check_snmp_synology [options] -h TARGET
+
+OPTIONS:
+    -a STRING
+        Authentication params for snmpwalk/ snmpget to connect to target; 
+        default: "-v2c -c public" (Snmpv2 with community string "public")
+    -h SNMPTARGET
+        Set a target to connect as fqdn or ip address; default: localhost
+    -f FILE
+        Read authentication from config file. See section 'CONFIG FILE' below.
+        default: "/etc/icinga2/snmp.cfg"
+
+    By default all checks will be executed. You can linit the executed checks
+    by naming single checks:
+
+    -s  System check:
+        - Show system data: model, serial number, DSM version
+        - System status
+        - Power status
+        - System fan Status
+        - CPU fan status
+    -d  Disk check: 
+        - status and temperature of each hard disk
+        - status of all raid volumes
+        - free disk space
+    -u  Update check; check switches to warning if an update is available
+    -t  Temerature check
+
+    -v  Enable detailed output of the checks. It is recommended for
+        system status and disk status.
+
+CONFIG FILE:
+    The config file can be multiline and has the syntax
+    [SNMPTARGET[,target2]]:[auth parameters]
+    The auth parameters set the version and all needed values to connect.
+    Snmp v2 uses a community string.
+    Snmp v3 is highly recommended (you should disable Snmp v2) and needs
+    a user and password.
+
+    Example:
+    server-01.example.com:-v 3 -l authnoPriv -a SHA -u snmpmonitor -A password-for-server-01
+    server-02.example.com,192.168.0.4:-v 3 -l authnoPriv -a SHA -u snmpmonitor -A password-for-server-02
+
+EXAMPLE:
+
+    check_snmp_synology -h server-01.example.com -v
+        Show complete Synology status of server-01 using connect data from 
+        /etc/icinga2/snmp.cfg
+
+    check_snmp_synology -h server-01.example.com -v -f /opt/somewhere/snmp.conf
+        Show complete Synology status of server-01 using connect data from 
+        custom config file
+
+    check_snmp_synology -h server-01.example.com -u
+        Make a single check if update is available.
+
+```
+
+## Examples
+
+### Complete status
+
+`./check_snmp_synology -h server-01.example.com -v`
+
+Shows the full set of status checks.
+The output is something like that:
+
+```txt
+OK:   Synology "RS3614xs+" (s/n: "1410M9N0*****", "DSM 7.1-42962")
+                          
+---------- INFORMATION    
+Synology model:           "RS3614xs+"
+Synology s/n:             "1410M9N0*****"
+DSM Version:              "DSM 7.1-42962"
+Update available:         Up to date (2)
+                          
+---------- SYSTEM         
+System Status:            Normal
+Power Status:             Normal
+System Fan Status:        Normal
+CPU Fan Status:           Normal
+NAS temperature:          40 °C
+                          
+---------- STORAGE        
+Number of disks:          12
+  "Disk 1" (model:"ST2000NM0008-2F3100") status: Normal (1) temperature: 29 °C 
+  "Disk 2" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 35 °C 
+  "Disk 3" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 35 °C 
+  "Disk 4" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 33 °C 
+  "Disk 5" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 34 °C 
+  "Disk 6" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 35 °C 
+  "Disk 7" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 35 °C 
+  "Disk 8" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 34 °C 
+  "Disk 9" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 35 °C 
+  "Disk 10" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 35 °C 
+  "Disk 11" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 35 °C 
+  "Disk 12" (model:"ST2000NM0033-9ZM175") status: Normal (1) temperature: 34 °C 
+                          
+Number of RAID volumes:   1
+  "Volume 1" status: Normal (1) - size 20282 GB, free 7514 GB (37%) 
+
+```
+
+### Check temperature only
+
+`./check_snmp_synology -h server-01.example.com -t`
+
+Without `-v` param you get a short status with a single line. For this check the details are useless.
+
+Next to the status you get a line with performance data.
+
+```txt
+OK: NAS temperature: 40 °C
+
+ |temp=40;;
+```
+
+### Check os update only
+
+`./check_snmp_synology -h server-01.example.com -u`
+
+Without `-v` param you get a short status with a single line. For this check the details are useless.
+
+```txt
+OK: Up to date
+```
+
+## SNMP authentication configuration
+
+In a configuration file you can put the authentication parameters for snmpget and snmpwalk.
+
+By default it reads /etc/icinga2/snmp.cfg - but you can use `-f FILENAME` to override it.
+
+```txt
+sudo cat /etc/icinga2/snmp.cfg 
+#
+# snmp-connections
+# SYNTAX: [hostname]:[params]
+#
+DEFAULT:-v 2c -c public
+server-01.example.com:-v 3 -l authnoPriv -a SHA -u imlmonitor -A password-for-server-01
+server-02.example.com:-v 3 -l authnoPriv -a SHA -u imlmonitor -A password-for-server-02
+```
diff --git a/docs/_index.md b/docs/_index.md
index 9ed5d8e4409b6f32e77e43a1208e76fdbb9f1586..7d306d9aa8292f24129bea32f56300ffea20aab3 100644
--- a/docs/_index.md
+++ b/docs/_index.md
@@ -14,4 +14,5 @@ We use Icinga graphite module to show performance data. The templates are locate
 * Checks: <https://git-repo.iml.unibe.ch/iml-open-source/icinga-checks>
 * Graphs (Graphite): <https://git-repo.iml.unibe.ch/iml-open-source/icinga-graphite-templates>
 
-📜 Licence: GNU GPL 3.0
+📜 Licence: GNU GPL 3.0 \
+📗 Docs: <https://os-docs.iml.unibe.ch/icinga-checks/>
\ No newline at end of file