Category: System File (系统文件)

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[CONTENT] Linux common parameters of /etc/fstab file

/dev/vg/lv_var /var xfs nodev,nosuid,noexec 0 0
/dev/vg/lv_var_log /var/log xfs nodev,nosuid,noexec,x-systemd.requires-mounts-for=/var 0 0

(
Add:
1) nodev parameter here means this directory can not be interpreted by devices or blocks
2) nosuid parameter here means no setuid files can be created in this directory
3) noexec parameter here means no files can be executed in this directory
4) x-systemd.requires-mounts-for=/var here parameter means /var/log directory can not be mounted until /var directory has been mounted
)

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[DEBUG] Linux resolve error code ‘DB version too old ……, expected …… for domain implicit_files!’

Error Code：

# useradd <account name>
DB version too old ......, expected ...... for domain implicit_files!
......

Or:

# chage -l <user name>
DB version too old ......, expected ...... for domain implicit_files!
......

Solution:

Step One: Create /etc/sssd/sssd.conf file

# vim /etc/sssd/sssd.conf

Add follow lines:

[sssd]
enable_files_domain = true

Step Two: Give /etc/sssd/sssd.conf file properly privilege

# chmod 600 /etc/sssd/sssd.conf

Step Three: Restart sssd service

# systemctl restart sssd

Reference:

https://access.redhat.com/solutions/7031304

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[CONTENT] Linux recommended swap size

Content:

For RHEL 6, RHEL 7, RHEL 8, RHEL 9

RAM sizeRecommended swap sizeRecommended swap size if allowing for hibernation
From 0 to 2GB 2 times the RAM size3 times the RAM size
From 2GB to 8GBThe same size of the RAM2 times the RAM size
From 8GB to 64GBAt least 4GB1.5 times the RAM size
From 64GBAt least 4GBHibernation is not recommended
RHEL 6, RHEL 7, RHEL 8, RHEL 9 Recommended Swap Size Table

Note: A 100GB swap is recommended if system with over 140 logical processes or over 3TB RAM

Reference:

https://access.redhat.com/solutions/15244

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[步骤] Linux journal 日志的永久存储

正文：

步骤一：理解 journal 日志存储机制

默认情况下，journal 的日志存储在 /run/log/journal，而 /run 目录只是一个临时目录。

将 Storage 参数设置为 persistent 后，journal 的日志将存储在 /var/log/journal，/var/log 则是一个永久的目录。

步骤二：将 journal 日志设置为永久存储

2.1 修改 /etc/systemd/journald.conf 文件

# vi /etc/systemd/journald.conf

将部分内容修改如下：

[Journal]
......
Storage=persistent
......

2.2 重启 systemd-journald 服务

# systemctl restart systemd-journald.service

参考文献：

https://linuxconfig.org/introduction-to-the-systemd-journal