gs_checkos

Context

gs_checkos helps you check the OS version information, control parameters, and disk configurations, and configure control parameters, I/O parameters, network parameters, and THP services.

Prerequisites

The hardware and network are working properly.
The trust relationship of user root among the hosts is normal.
Only user root is authorized to run the gs_checkos command.

Syntax

Check OS information.

gs_checkos -i ITEM [-f HOSTFILE] [-h HOSTNAME] [-X XMLFILE] [--detail] [-o OUTPUT] [-l LOGFILE]

Display help information.
```
gs_checkos -? | --help 
```
Display version information.
```
gs_checkos -V | --version
```

Parameter Description

-i
Specifies the number of a check item. The format is -i A, -i B1, -i A1 -i A2, or - i A1,A2.
Value range: A1…A14 and B1…B8
NOTE:
Items from A1 to A14 indicate that OS parameters need to be checked but not to be set.
Items from B1 to B8 indicate that system parameters need to be set to expected values.
Items A and items B cannot be simultaneously set.
For details, see Table 1.
-f
Specifies the file of a host name list.
NOTE: The -f and -h parameters cannot be used together.
Value range: a host name list
-h
Specifies the name of a host to be checked. You can specify multiple hosts and separate the hosts with commas (,).
Value range: a host name of openGauss. If no host is specified, the current host is checked.
-X
Specifies the XML configuration file of openGauss.
--detail
Displays detailed check results.
-o
Specifies the file for saving OS check reports.
If this parameter is not specified, OS check results are displayed on the screen.
-l
Specifies a log file and its save path.
Default value: /tmp/gs_checkos/gs_checkos-YYYY-MM-DD_hhmmss.log
-?, --help
Displays help information.
-V, --version
Displays version information.

Table 1 OS check items

Number	Check Item	Description
A1	OS version status	Check the OS version. Ensure that the host platform supports SUSE11, SUSE12, RHEL, or CentOS. In addition, you need to ensure that the all host platforms of openGauss belong to the same hybrid range.
A2	Kernel version status	Check the kernel version.
A3	Unicode status	Check the character set. Ensure that the character sets of openGauss hosts are consistent.
A4	Time zone status	Checks the time zone setting. Ensure that the time zones of openGauss hosts are consistent.
A5	Swap memory status	Check the swap partition. Ensure that the swap partition size of each host is less than or equals to the total memory size of the host.
A6	System control parameters status	Check the kernel parameter. Ensure that the parameter value of the current kernel is consistent with the default value. For details, see OS Parameters.
A7	File system configuration status	Check the system file handle. Ensure that the parameter value of the system file handle is greater than or equal to 1000000. Check the thread stack size: Ensure that the thread size is greater than or equal to 3072 KB. Check the maximum available virtual memory of processes. Ensure that the maximum available virtual memory of system processes is unlimited.
A8	Disk configuration status	Check the hard disk mounting parameter. Ensure that the disk format is XFS and its mounting mode is "rw,noatime,inode64,allocsize=16m".
A9	Pre-read block size status	Check the pre-read parameter. Ensure that the expected value of the pre-read parameter is 16384.
A10	IO scheduler status	Check the I/O scheduling policy. Ensure that the I/O scheduling policy is deadline.
A11	Network card configuration status	Check the NIC smaller than 10GE. Ensure that mtu of the NIC is 1500. Check the NIC larger than 10GE. When the NIC is in unbinding mode and is a 10GE card, ensure that the value of mtu is 1500 and the value of rx/tx is greater than or equal to 4096. When the NIC is in binding mode, ensure that the type of each binding NIC is 10GE, the value of mtu is 1500, and the value of rx/tx is greater than or equal to 4096. The NIC of openGauss's peripheral devices (such as switches) should be set to the same as that of the openGauss hosts.
A12	Time consistency status	Check the time consistency status. Ensure that the NTP service is started and the system time deviation of each openGauss host does not exceed 60s.
A13	Firewall service status	Check the firewall status. Ensure that the firewall is disabled.
A14	THP service status	Check the THP service status. Ensure that the THP service is disabled.
B1	Set system control parameters	Sets the kernel parameter. When the actual value does not meet check requirements, reset the parameter whose result is Abnormal. Do not set the Warning parameter here. You can set the value of Warning as needed.
B2	Set file system configuration value	Sets the parameter of system file handles. Set the number of system file handles if it is less than 1000000. Set the thread stack size. Set the thread stack size if it is less than 3072 KB. Set the maximum available virtual memory of processes: If the maximum available virtual memory of system processes is not unlimited, change it to unlimited.
B3	Set pre-read block size value	Set the hard disk pre-read parameter: When the actual value is less than 16384, reset the parameter.
B4	Set IO scheduler value	Set the I/O configuration item. If the actual value of the system is not deadline, reset the parameter.
B5	Set network card configuration value	Set the 10GE NIC parameters. Set the rx and tx parameters that do not meet 10GE NIC requirements. Do not set the mtu parameter.
B6	Set THP service	Set the THP service. If the THP service is enabled, disable it.
B7	Set RemoveIPC value	Check EulerOS attributes. Set the value of RemoveIPC in files /usr/lib/systemd/system/systemd-logind.service and /etc/systemd/logind.conf to no.
B8	Set Session Process	Set a remote device to inherit default system resources. Modify the /etc/pam.d/sshd service file and add the session required pam_limits.so configuration item to control resources used by users.

NOTE:
Item A6 needs to be checked based on the [/etc/sysctl.conf] and [SUGGEST:/etc/sysctl.conf] domains in the check_list.conf configuration file.
If the parameter value in [/etc/sysctl.conf] differs from the actual value, an Abnormal message is displayed during the check of item A6. You can set the parameter in item B1.
If the parameter value in [SUGGEST:/etc/sysctl.conf] differs from the actual value, a Warning message is displayed during the check of item A6. You can manually set the parameter in item B1 as needed.
Item A7 checks items specified by the open file parameter in the [/etc/security/ limits.conf] domain in the check_list.conf configuration file. You can set the parameter in item B2.
The mtu, rx, and tx parameters of item A11 need to be checked based on the [/sbin/ifconfig] domain in the check_list.conf configuration file. You can set the rx and tx parameters using item B5 and set the mtu parameter manually.
Use configured gs_checkos kernel parameter value and file handles parameter value to restart the new session.

OS Parameters

Table 2 OS parameters

Parameter	Description	Recommended Value
net.ipv4.tcp_max_tw_buckets	Specifies the maximum number of TCP/IP connections concurrently remaining in the TIME_WAIT state. If the number of TCP/IP connections concurrently remaining in the TIME_WAIT state exceeds the value of this parameter, the TCP/IP connections in the TIME_WAIT state will be released immediately, and alarm information will be printed.	10000
net.ipv4.tcp_tw_reuse	Reuses sockets whose status is TIME-WAIT for new TCP connections. 0: This function is disabled. 1: This function is enabled.	1
net.ipv4.tcp_tw_recycle	Rapidly reclaims sockets whose status is TIME-WAIT in TCP connections. 0: This function is disabled. 1: This function is enabled.	1
net.ipv4.tcp_keepalive_time	Specifies how often Keepalived messages are sent through TCP connections when Keepalived is enabled.	30
net.ipv4.tcp_keepalive_probes	Specifies the number of Keepalived detection packets sent through a TCP connection before the connection is regarded invalid. The product of the parameter value multiplied by the value of the tcp_keepalive_intvl parameter determines the response timeout duration after a Keepalived message is sent through a connection.	9
net.ipv4.tcp_keepalive_intvl	Specifies how often a detection packet is re-sent when the previous packets are not acknowledged.	30
net.ipv4.tcp_retries1	Specifies the maximum TCP reattempts during the connection establishment process.	5
net.ipv4.tcp_syn_retries	Specifies the maximum SYN packet reattempts in the TCP.	5
net.ipv4.tcp_synack_retries	Specifies the maximum SYN response packet reattempts in the TCP.	5
net.sctp.path_max_retrans	Specifies the maximum SCTP reattempts.	10
net.sctp.max_init_retransmits	Specifies the maximum INIT packet reattempts in the SCTP.	10
net.sctp.association_max_retrans	Specifies the maximum reattempts of a single logical connection in the SCTP.	10
net.sctp.hb_interval	Specifies the retransmission interval of heartbeat detection packets in the SCTP.	30000
net.ipv4.tcp_retries2	Specifies the number of times that the kernel re-sends data to a connected remote host. A smaller value leads to earlier detection of an invalid connection to the remote host, and the server can quickly release this connection. If "connection reset by peer" is displayed, increase the value of this parameter to avoid the problem.	12
vm.overcommit_memory	Specifies the kernel check method during memory allocation. 0: The system accurately calculates the current available memory. 1: The system returns a success message without a kernel check. 2: The system returns a failure message if the memory size you have applied for exceeds the result of the following formula: Total memory size x Value of vm.overcommit_ratio/100 + Total SWAP size. The default value for is 2, which is too conservative. The recommended value is 0. If memory usage is high, set this parameter to 1.	0
net.sctp.sndbuf_policy	Specifies the buffer allocation policy on the SCTP sender. 0: The buffer is allocated by connection. 1: The buffer is allocated by association.	0
net.sctp.rcvbuf_policy	Specifies the buffer allocation policy on the SCTP receiver. 0: The buffer is allocated by connection. 1: The buffer is allocated by association.	0
net.sctp.sctp_mem	Specifies the maximum free memory of the kernel SCTP stack. Three memory size ranges in the unit of page are provided: min, default, and max. If the value is max, packet loss occurs.	94500000 915000000 927000000
net.sctp.sctp_rmem	Specifies the total free memory for receiving data in the kernel SCTP stack. Three memory size ranges in the unit of page are provided: min, default, and max. If the value is max, packet loss occurs.	8192 250000 16777216
net.sctp.sctp_wmem	Specifies the total free memory for sending data in the kernel SCTP stack. Three memory size ranges in the unit of page are provided: min, default, and max. If the value is max, packet loss occurs.	8192 250000 16777216
net.ipv4.tcp_rmem	Specifies the free memory in the TCP receiver buffer. Three memory size ranges in the unit of page are provided: min, default, and max.	8192 250000 16777216
net.ipv4.tcp_wmem	Specifies the free memory in the TCP sender buffer. Three memory size ranges in the unit of page are provided: min, default, and max.	8192 250000 16777216
net.core.wmem_max	Specifies the maximum size of the socket sender buffer.	21299200
net.core.rmem_max	Specifies the maximum size of the socket receiver buffer.	21299200
net.core.wmem_default	Specifies the default size of the socket sender buffer.	21299200
net.core.rmem_default	Specifies the default size of the socket receiver buffer.	21299200
net.ipv4.ip_local_port_range	Specifies the range of temporary ports that can be used by a physical server.	26000-65535
kernel.sem	Specifies the kernel semaphore.	250 6400000 1000 25600
vm.min_free_kbytes	Specifies the minimum free physical memory reserved for unexpected page breaks.	5% of the total system memory
net.core.somaxconn	Specifies the maximum length of the listening queue of each port. This is a global parameter.	65535
net.ipv4.tcp_syncookies	Specifies whether to enable SYN cookies to guard the OS against SYN attacks when the SYN waiting queue overflows. 0: The SYN cookies are disabled. 1: The SYN cookies are enabled.	1
net.sctp.addip_enable	Specifies whether dynamic address reset of the SCTP is enabled. 0: This function is disabled. 1: This function is enabled.	0
net.core.netdev_max_backlog	Specifies the maximum number of data packets that can be sent to the queue when the rate at which the network device receives data packets is higher than that at which the kernel processes the data packets.	65535
net.ipv4.tcp_max_syn_backlog	Specifies the maximum number of unacknowledged connection requests to be recorded.	65535
net.ipv4.tcp_fin_timeout	Specifies the default timeout duration.	60
kernel.shmall	Specifies the total shared free memory of the kernel.	1152921504606846720
kernel.shmmax	Specifies the maximum value of a shared memory segment.	18446744073709551615
net.ipv4.tcp_sack	Specifies whether selective acknowledgment is enabled. The selective acknowledgment on out-of-order packets can increase system performance. Restricting users to sending only lost packets (for wide area networks) should be enabled, but this will increase CPU usage. 0: This function is disabled. 1: This function is enabled.	1
net.ipv4.tcp_timestamps	Specifies whether the TCP timestamp (12 bytes are added in the TCP packet header) enables a more accurate RTT calculation than the retransmission timeout (for details, see RFC 1323) for better performance. 0: This function is disabled. 1: This function is enabled.	1
vm.extfrag_threshold	When system memory is insufficient, Linux will score the current system memory fragments. If the score is higher than the value of vm.extfrag_threshold, kswapd triggers memory compaction. When the value of this parameter is close to 1000, the system tends to swap out old pages when processing memory fragments to meet the application requirements. When the value of this parameter is close to 0, the system tends to do memory compaction when processing memory fragments.	500
vm.overcommit_ratio	When the system uses the algorithms where memory usage never exceeds the thresholds, the total memory address space of the system cannot exceed the value of swap+RAM multiplied by the percentage specified by this parameter. When the value of vm.overcommit_memory is set to 2, this parameter takes effect.	90
/sys/module/sctp/parameters/no_checksums	Specifies whether checksum is disabled in SCTP.	0
MTU	Specifies the maximum transmission unit (MTU) for a node NIC. The default value is 1500 in the OS. You can set it to 8192 to improve the performance of sending and receiving data using SCTP.	8192

File System Parameters

soft nofile
Indicates the soft restriction. The number of file handles used by a user can exceed this setting value, but an alarm message will be sent if the value is exceeded.
Recommended value: 1000000
hard nofile
Indicates the hard restriction. The number of file handles used by a user cannot exceed this setting value.
Recommended value: 1000000
stack size
Indicates the thread stack size.
Recommended value: 3072

Examples

Run the following commands to check the OS parameters:

gs_checkos -i A -h plat1 -X /opt/software/openGauss/clusterconfig.xml --detail -o /var/log/checkos 
Performing operation system check/set. Output the result to the file /var/log/checkos.
Operation system check/set is completed.
Total numbers:14. Abnormal numbers:0. Warning number:1.

Query check results.

vim /var/log/checkos 
Checking items:
    A1. [ OS version status ]                                   : Normal
    A2. [ openGauss version status ]                               : Normal
    A3. [ Unicode status ]                                      : Normal
    A4. [ Time zone status ]                                    : Normal
    A5. [ Swap memory status ]                                  : Normal
    A6. [ System control parameters status ]                    : Normal
    A7. [ File system configuration status ]                    : Normal
    A8. [ Disk configuration status ]                           : Normal
    A9. [ Pre-read block size status ]                          : Normal
    A10.[ IO scheduler status ]                                 : Normal
    A11.[ Network card configuration status ]                   : Normal
    A12.[ Time consistency status ]                             : Warning
    A13.[ Firewall service status ]                             : Normal
    A14.[ THP service status ]                                  : Normal

Helpful Links

gs_check, gs_checkperf