[Linux]经典面试题 - 系统管理 - 资源查看
目录
一、操作系统
1.1 uname -a
[root@localhost /]# uname -a
Linux localhost.localdomain 4.18.0-305.3.1.el8.x86_64 #1 SMP Tue Jun 1 16:14:33 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
二、进程管理
2.1 ps -l
[root@localhost /]# ps -l
F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD
0 S 0 5360 3838 0 80 0 - 59339 - pts/0 00:00:00 bash
0 R 0 6273 5360 0 80 0 - 63809 - pts/0 00:00:00 ps
ps -l，仅列出与bash相关的进程，即最上层的父进程是bash，而不是systemd。
字段说明：
- F：Process Flags 进程标志
- 4：表示该进程的权限为root；
- 1：表示此紫禁城仅进行fork而没有实际执行。
- S：Process Stat 进程状态
- R：运行中；
- S：睡眠(idle)状态，可被唤醒(signal)。
- D：不可被唤醒的睡眠状态，通常是在等待IO
- T：停止(stop)状态，可能被暂停或者出错。
- Z：僵尸(zombie)进程，进程已经终止但却无法被移除至内存外。
- UID：此进程所有者ID
- PID：此进程的PID号
- PPID：此进程的父进程PID号
- C：代表CPU使用率。
- PRI：Priority 优先级，被CPU所执行的优先级，数值越小约先被执行。
- TTY：登入的终端位置。
- TIME：进程实际花费CPU运作的时间。
- CMD：哪个指令触发的这个进程。
2.2 ps aux
[root@localhost /]# ps aux | head -7
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.1 0.3 245596 14224 ? Ss 17:06 0:03 /usr/lib/systemd/systemd --switched-root --system --deserialize 18
root 2 0.0 0.0 0 0 ? S 17:06 0:00 [kthreadd]
root 3 0.0 0.0 0 0 ? I< 17:06 0:00 [rcu_gp]
root 4 0.0 0.0 0 0 ? I< 17:06 0:00 [rcu_par_gp]
root 6 0.0 0.0 0 0 ? I< 17:06 0:00 [kworker/0:0H-events_highpri]
root 9 0.0 0.0 0 0 ? I< 17:06 0:00 [mm_percpu_wq]
ps aux，观察的是系统所有的进程。
字段说明：
- USER：该进程所有者。
- PID：该进程标识符。
- %CPU：该进程使用的CPU占比。
- %MEM：该进程使用的内存占比。
- VSZ：该进程占用的虚拟内存量（Kb）。
- RSS：该进程占用的固定的内存量（kb）。
- TTY：该进程是在哪个终端机上面运作，若与终端机无关则显示？。
- STAT：该进程状态，同ps -l。
- START：该进程被触发启动的时间。
- TIME：该进程实际使用CPU运作的时间。
- COMMAND：该进程的实际指令为何？
2.3 ps aux | egrep '(a|b)'
[root@localhost /]# ps aux | egrep '(cron|rsyslog)'
root 1300 0.1 0.3 209440 12136 ? Ssl 20:11 0:00 /usr/sbin/rsyslogd -n
root 1324 0.0 0.0 233084 2752 ? Ss 20:11 0:00 /usr/sbin/crond -n
root 2853 0.0 0.0 221928 1152 pts/0 S+ 20:12 0:00 grep -E --color=auto (cron|rsyslog)
ps aux | egrep '(cron|rsyslog)'，用来查找多个服务。
三、CPU
3.1 lscpu
[root@localhost /]# lscpu
Architecture: x86_64 #CPU架构
CPU op-mode(s): 32-bit, 64-bit #操作模式
Byte Order: Little Endian
CPU(s): 2 #CPU核心个数
On-line CPU(s) list: 0,1
Thread(s) per core: 1
Core(s) per socket: 1
Socket(s): 2 #线程数
NUMA node(s): 1
Vendor ID: GenuineIntel
BIOS Vendor ID: GenuineIntel
CPU family: 6
Model: 60
Model name: Intel(R) Xeon(R) CPU E3-1231 v3 @ 3.40GHz
BIOS Model name: Intel(R) Xeon(R) CPU E3-1231 v3 @ 3.40GHz
Stepping: 3
CPU MHz: 3392.148
BogoMIPS: 6784.29
Virtualization: VT-x #硬件辅助虚拟化 VT-x
Hypervisor vendor: VMware
Virtualization type: full #虚拟化类型：硬件辅助的全虚拟化
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 8192K
NUMA node0 CPU(s): 0,1
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc cpuid pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm cpuid_fault invpcid_single pti ssbd ibrs ibpb stibp tpr_shadow vnmi ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 invpcid xsaveopt arat md_clear flush_l1d arch_capabilities #指令集
四、内存
4.1 free -mh
[root@localhost /]# free -mh
total used free shared buff/cache available
Mem: 3.6Gi 998Mi 1.8Gi 16Mi 821Mi 2.4Gi
Swap: 8.0Gi 0B 8.0Gi
free -mh，查看内存占用。
字段说明：
- buff/cache：在这里，buff指的是Buffer cache；cache指的是Page cache。
五、硬盘
5.1 df-hT
[root@localhost /]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 1.8G 0 1.8G 0% /dev
tmpfs tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs tmpfs 1.9G 9.7M 1.9G 1% /run
tmpfs tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/mapper/cl-root xfs 91G 5.5G 86G 6% /
/dev/sda1 ext4 976M 241M 669M 27% /boot
tmpfs tmpfs 371M 28K 371M 1% /run/user/0
/dev/sr0 iso9660 1.6G 1.6G 0 100% /run/media/root/CentOS-8-2-2004-x86_64-dvd
5.2 lsblk
[root@localhost /]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 100G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 99G 0 part
├─cl-root 253:0 0 91G 0 lvm /
└─cl-swap 253:1 0 8G 0 lvm [SWAP]
sr0 11:0 1 1.6G 0 rom /run/media/root/CentOS-8-2-2004-x86_64-dvd
5.3 fdisk -l
[root@localhost /]# fdisk -l
Disk /dev/sda: 100 GiB, 107374182400 bytes, 209715200 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x58f49df1
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 2099199 2097152 1G 83 Linux
/dev/sda2 2099200 209715199 207616000 99G 8e Linux LVM
Disk /dev/mapper/cl-root: 91 GiB, 97706311680 bytes, 190832640 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/cl-swap: 8 GiB, 8589934592 bytes, 16777216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
5.4 parted
[root@localhost /]# parted /dev/sda print
Model: VMware, VMware Virtual S (scsi)
Disk /dev/sda: 107GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 1049kB 1075MB 1074MB primary ext4 boot
2 1075MB 107GB 106GB primary lvm
六、网络
6.1 ip addr
[root@localhost /]# ip addr
1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <broadcast,multicast,up,lower_up> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:dc:c2:3e brd ff:ff:ff:ff:ff:ff
inet 192.168.9.100/24 brd 192.168.9.255 scope global noprefixroute ens33
valid_lft forever preferred_lft forever
inet6 fe80::5cf2:974e:5067:d5ab/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: virbr0: <no-carrier,broadcast,multicast,up> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
link/ether 52:54:00:d3:07:24 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
4: virbr0-nic: <broadcast,multicast> mtu 1500 qdisc fq_codel master virbr0 state DOWN group default qlen 1000
link/ether 52:54:00:d3:07:24 brd ff:ff:ff:ff:ff:ff
6.2 ifconfig
[root@localhost /]# ifconfig
ens33: flags=4163<up,broadcast,running,multicast> mtu 1500
inet 192.168.9.100 netmask 255.255.255.0 broadcast 192.168.9.255
inet6 fe80::5cf2:974e:5067:d5ab prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:dc:c2:3e txqueuelen 1000 (Ethernet)
RX packets 171 bytes 30453 (29.7 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 188 bytes 18577 (18.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<up,loopback,running> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 24 bytes 1976 (1.9 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 24 bytes 1976 (1.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
virbr0: flags=4099<up,broadcast,multicast> mtu 1500
inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255
ether 52:54:00:d3:07:24 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
