IOPS Input/Output Operations Per Second. 用于衡量数据传输操作（Rate of Data transfer operations）的频率。对于硬盘 I/O （Disk I/O）来说，指 每秒发生的读写请求 。
Throughput 吞吐量 。在网络通信中，主要指 数据传输速率（Data Rate, bytes/bits per second） 。在其他上下文（Contexts,如 Databases），Throughput 通常指 Operation Rate（Operations Per Second or Transactions Per Second）
# systemd-analyze critical-chain The time when unit became active or started is printed after the "@" character. The time the unit took to start is printed after the "+" character.
UEFI 包含了一个平台相关（platform-related）的 数据表（data table） ，以及 可以被 OS Loader 调用的 Boot and Runtime Service Calls 。这些信息定义了为支持 UEFI ，固件（Firmwares）或者计算机硬件（Hardwares）应该实现的接口和数据结构（Interfaces and Structures）。
PAM 中的 Control Flags 用于决定返回什么样的状态。下表列出了 PAM 配置中的相关的 Control Flags 及其响应
Control Flag
Response Handle
required
If failed, returns a failure status to the application, after the rest of the contexts have been run in the stack. For example, a requisite control might cause a login to fail if someone types in an invalid user. But the user might not be told of the failure until after entering a password, hiding the fact that it was the bad username that caused the failure
requisite
If failed, returns a failure status to the application immediately without running the rest of the stack 。 (Be careful where you place this control in the stack.) For example, a requisite control might require key-based authentication and fail immediately when a valid key is not provided . In that case, it could fail before even prompting for a username/password.
sufficient
- If failed, the module status is ignored. - If successful, then a success status is immediately returned to the application without running the rest of the stack. (Be careful where you place this control in the stack.)
optional
This control flag is important only for the final overall return status of success or failure . Think of it as a tiebreaker. When the other modules in the configuration file stack return statuses that are neither clear-cut failure nor success statuses, this optional module’s status is used to determine the final status or break the tie. In cases where the other modules in the stack are returning a clear-cut path of failure or success, this status is ignored.
include
Get all the return statuses from this particular PAM configuration file’s stack to include in this stack’s overall return status. It’s as if the entire stack from the named configuration file is now in this configuration file
substack
Similar to the include control flag, except for how certain errors and evaluations affect the main stack. This forces the included configuration file stack to act as a substack to the main stack. Thus, certain errors and evaluations affect only the substack and not the main stack.
Encryption ： 将 Plain Text 转换为 Ciphertext 的过程，通常使用一种加密算法（Encrypt Algorithm）
Decryption ： 解密，将 Ciphertext 转换为 Plain Text 的过程，通常使用和加密算法（Encrypt Algorithm）相对应的解密算法（Decrypt Algorithms）
Cipher ： 加密和解密过程中算法使用的密码。
Block Cipher ： 在对数据进行加密之前，需要首先将其分割成块（Block）
Stream Cipher ： 加密过程中无需将其分割成块（Block）
Key ： 通常值密钥对（公钥/私钥）
以下是一些较为经典的加密算法
Algorithm
Description
AES Advanced Encryption Standard, also called Rijndael
- Symmetric Cryptography - Block Cipher 。encrypting data in 128-, 192-, 256-, 512- bit， blocks using a 128-, 192-, 256, or 512-bit key
Blowfish
- Symmetric Cryptography - Block Cipher 。encrypting data in 64-bit blocks using the same 32-bit to 448-bit keys for encrypting/decrypting.
CAST5
- Symmetric Cryptography - Block Cipher 。 encrypting data in 64-bit blocks using the same up to 128-bit key for encrypting/decrypting.
DES Data Encryption Standard
已经被认为是不安全的 - Symmetric Cryptography - Block Cipher 。encrypting data in 64-bit blocks using the same 56-bit key for encrypting/decrypting.
3DES
增强的 DES 加密算法 - Symmetric Cryptography Data is encrypted up to 48 times with three different 56-bit keys before the encryption process is completed.
IDEA
- Symmetric Cryptography - Block Cipher 。 encrypting data in 64-bit blocks using the same 128-bit key for encrypting/decrypting
RC5
- Symmetric Cryptography - Block Cipher 。 encrypting data in 32-, 64-``, or 128- bit blocks ，using the same up to 2,048-bit keys for encrypting/decrypting
RC6
- Symmetric Cryptography Same as RC5, but slightly faster
EI Gamal
- Asymmetric Cryptography Uses two keys derived from a logarithm algorithm
Elliptic Curve Cryptosystems
- Asymmetric Cryptography Uses two keys derived from an algorithm containing two randomly chosen points on an elliptic curve.
RC4 also called ArcFour or ARC4
- Stream Cipher encrypting data in 64-bit blocks using a variable key size for encrypting/decrypting.
Linux 审计系统提供了一种方式来跟踪系统上与安全相关的信息。根据预配置的规则，审计会生成日志条目，来尽可能多地记录系统上所发生的事件的相关信息。对于关键任务环境而言至关重要，可用来确定安全策略的违反者及其所执行的操作。审计不会为您的系统提供额外的安全，而是用于发现系统上使用的安全策略的违规。可以通过其他安全措施(如 SELinux)进一步防止这些违规。 [1]
# rpm -Va .......T. /usr/src/kernels/3.10.0-1160.114.2.el7.x86_64/virt/lib/Kconfig .......T. /usr/src/kernels/3.10.0-1160.114.2.el7.x86_64/virt/lib/Makefile S.5....T. c /root/.bash_profile S.5....T. c /root/.bashrc .M....... /var/run/supervisor missing /etc/filebeat/fields.yml SM5....T. c /etc/filebeat/filebeat.yml ....L.... c /etc/pam.d/fingerprint-auth ....L.... c /etc/pam.d/password-auth ....L.... c /etc/pam.d/postlogin ....L.... c /etc/pam.d/smartcard-auth ....L.... c /etc/pam.d/system-auth
要查看 parted 常见用法，可以参考 parted --help 或在交互模式中使用 help 指令
查看分区表信息
要查看系统上的分区信息，使用以下方式之一
parted -l
# parted -l Model: Amazon Elastic Block Store (nvme) Disk /dev/nvme0n1: 85.9GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags:
Number Start End Size File system Name Flags 14 1049kB 5243kB 4194kB bios_grub 15 5243kB 116MB 111MB fat32 boot, esp 1 116MB 85.9GB 85.8GB ext4
Model: Amazon Elastic Block Store (nvme) Disk /dev/nvme1n1: 107GB Sector size (logical/physical): 512B/512B Partition Table: msdos Disk Flags:
Number Start End Size Type File system Flags 1 1049kB 53.7GB 53.7GB primary ext4
Model: Unknown (unknown) Disk /dev/zram0: 33.2GB Sector size (logical/physical): 4096B/4096B Partition Table: loop Disk Flags:
Number Start End Size File system Flags 1 0.00B 33.2GB 33.2GB linux-swap(v1)
parted 交互模式，在交互模式中使用指令 p
# parted GNU Parted 3.4 Using /dev/nvme0n1 Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p Model: Amazon Elastic Block Store (nvme) Disk /dev/nvme0n1: 85.9GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags:
Number Start End Size File system Name Flags 14 1049kB 5243kB 4194kB bios_grub 15 5243kB 116MB 111MB fat32 boot, esp 1 116MB 85.9GB 85.8GB ext4
(parted) mklabel gpt Warning: The existing disk label on /dev/nvme1n1 will be destroyed and all data on this disk will be lost. Do you want to continue? Yes/No? Yes (parted)
(parted) p Model: SanDisk Ultra (scsi) Disk /dev/nvme1n1: 123GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End Size File system Name Flags 1 1049kB 123GB 123GB xfs alldisk
使用 quit 指令退出 parted 交互模式。
fdisk 交互模式中，只有最终执行了 w 命令保存，对硬盘的操作才会最终生效，和 fdisk 不同，parted 命令对硬盘的更改立即生效
