Expand linux centos7 partition

from here very easy

Steps

1. Shut down the VM from Hypervisor

 

2. Expand the disk capacity from settings with your desired value. Here we choose to expand the VHD with additional 60 GB space.

3. Start the VM from the hypervisor.

4. Login to virtual machine console as root.

5. Execute below command to check the disk space.

fdisk -l

6. Now execute this below command to initialize the expanded space and mount it.

fdisk /dev/sda

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').

7. After this enter ‘n’ in the next line for creating new partition.

Command action
e extended
p primary partition (1-4)
p

8. Then assign the partition number you wish based on your existing partition numbering.

Partition number (1-4): 3

Partition number (1-4): 3
Hex code (type L to list codes): 8e
Changed system type of partition 3 to 8e (Linux LVM)

9. In the next line choose code ‘8e’ for select the LINUX OS

Hex code (type L to list codes): 8e

Hex code (type L to list codes): 8e
Changed system type of partition 3 to 8e (Linux LVM)

10. Next enter ‘w’ to proceed further.

Command (m for help): w

Command (m for help): w
The partition table has been altered!
 
Calling ioctl() to re-read partition table.
 
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

11. Reboot the system.

12. Now we need to create physical & logical volumes execute below command to create physical volume.

pvcreate /dev/sda3

13. Execute below command to get the name of current Volume Group

vgdisplay

14. Execute below command to extend the Volume Group with /dev/sda3

vgextend VolGroup /dev/sda3

15. Execute below command to get Logical Volume path.

lvdisplay

16. Execute below command to extend the Logical Volume with /dev/sda3

lvextend /dev/VolGroup/lv_root /dev/sda3

17. Execute below command to update the Logical Volume

xfs_growfs /dev/VolGroup/lv_root

18. Check for the new disk space.

>df -h

19. Your Disk space is now successfully increased with 60 GB.

How to know if a disk is an SSD or an HDD Linux Centos 7

I needed to do this on the VPS and none of the provided solutions worked for me,

this answer did the trick

https://serverfault.com/questions/551453/how-do-i-verify-that-my-hosting-provider-gave-me-ssds/551495#551495

so, it is about reading random data from the drive and assessing the time.

time for i in `seq 1 1000`; do
    dd bs=4k if=/dev/sda count=1 skip=$(( $RANDOM * 128 )) >/dev/null 2>&1;
done

here are my results for SSD

real    0m1.375s
user    0m0.285s
sys     0m0.944s

and HDD

real    0m14.249s
user    0m0.752s
sys     0m6.284s

8 commands to check cpu information on Linux

1. /proc/cpuinfo

The /proc/cpuinfo file contains details about individual cpu cores. Output its contents with less or cat.

$ less /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Intel(R) Core(TM)2 Quad CPU    Q8400  @ 2.66GHz
stepping        : 10
microcode       : 0xa07
cpu MHz         : 1998.000
cache size      : 2048 KB
physical id     : 0
siblings        : 4
core id         : 0
cpu cores       : 4
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm dtherm tpr_shadow vnmi flexpriority
bogomips        : 5303.14
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

Every processor or core is listed separately the various details about speed, cache size and model name are included in the description.

To count the number of processing units use grep with wc

$ cat /proc/cpuinfo | grep processor | wc -l
4
The number of processors shown by /proc/cpuinfo might not be the actual number of cores on the processor. For example a processor with 2 cores and hyperthreading would be reported as a processor with 4 cores.

To get the actual number of cores, check the core id for unique values

$ cat /proc/cpuinfo | grep 'core id'
core id         : 0
core id         : 2
core id         : 1
core id         : 3

So there are 4 different core ids. This indicates that there are 4 actual cores.

2. lscpu

lscpu is a small and quick command that does not need any options. It would simply print the cpu hardware details in a user-friendly format.

$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    1
Core(s) per socket:    4
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 23
Stepping:              10
CPU MHz:               1998.000
BogoMIPS:              5303.14
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              2048K
NUMA node0 CPU(s):     0-3

3. hardinfo

Hardinfo is a gtk based gui tool that generates reports about various hardware components. But it can also run from the command line only if there is no gui display available.

$ hardinfo | less

It would produce a large report about many hardware parts, by reading files from the /proc directory. The cpu information is towards the beginning of the report. The report can also be written to a text file.

Hardinfo also performs a few benchmark tests taking a few minutes before the report is displayed.

4. lshw

The lshw command can display limited information about the cpu. lshw by default shows information about various hardware parts, and the ‘-class’ option can be used to pickup information about a specific hardware part.

$ sudo lshw -class processor
  *-cpu                   
       description: CPU
       product: Intel(R) Core(TM)2 Quad CPU    Q8400  @ 2.66GHz
       vendor: Intel Corp.
       physical id: 0
       bus info: [email protected]
       version: Intel(R) Core(TM)2 Quad CPU    Q8400  @ 2.66GHz
       slot: LGA 775
       size: 1998MHz
       capacity: 4GHz
       width: 64 bits
       clock: 333MHz
       capabilities: fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx x86-64 constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm dtherm tpr_shadow vnmi flexpriority cpufreq

The vendor, model and speed of the processor are being shown correctly. However it is not possible to deduce the number of cores on the processor from the above output.

5. nproc

The nproc command just prints out the number of processing units available. Note that the number of processing units might not always be the same as number of cores.

$ nproc
4

6. dmidecode

The dmidecode command displays some information about the cpu, which includes the socket type, vendor name and various flags.

$ sudo dmidecode -t 4
# dmidecode 2.12
SMBIOS 2.4 present.

Handle 0x0000, DMI type 4, 35 bytes
Processor Information
        Socket Designation: LGA 775
        Type: Central Processor
        Family: Pentium D
        Manufacturer: Intel(R) Corporation
        ID: 7A 06 01 00 FF FB EB BF
        Signature: Type 0, Family 6, Model 23, Stepping 10
        Flags:
                FPU (Floating-point unit on-chip)
                VME (Virtual mode extension)
                DE (Debugging extension)
                PSE (Page size extension)
                TSC (Time stamp counter)
                MSR (Model specific registers)
                PAE (Physical address extension)
                MCE (Machine check exception)
                CX8 (CMPXCHG8 instruction supported)
                APIC (On-chip APIC hardware supported)
                SEP (Fast system call)
                MTRR (Memory type range registers)
                PGE (Page global enable)
                MCA (Machine check architecture)
                CMOV (Conditional move instruction supported)
                PAT (Page attribute table)
                PSE-36 (36-bit page size extension)
                CLFSH (CLFLUSH instruction supported)
                DS (Debug store)
                ACPI (ACPI supported)
                MMX (MMX technology supported)
                FXSR (FXSAVE and FXSTOR instructions supported)
                SSE (Streaming SIMD extensions)
                SSE2 (Streaming SIMD extensions 2)
                SS (Self-snoop)
                HTT (Multi-threading)
                TM (Thermal monitor supported)
                PBE (Pending break enabled)
        Version: Intel(R) Core(TM)2 Quad CPU    Q8400  @ 2.66GHz
        Voltage: 1.6 V
        External Clock: 333 MHz
        Max Speed: 4000 MHz
        Current Speed: 2666 MHz
        Status: Populated, Enabled
        Upgrade: Socket LGA775
        L1 Cache Handle: 0x0003
        L2 Cache Handle: 0x0001
        L3 Cache Handle: Not Provided
        Serial Number: Not Specified
        Asset Tag: Not Specified
        Part Number: Not Specified

7. cpuid

The cpuid command fetches CPUID information about Intel and AMD x86 processors.

The program can be installed with apt on ubuntu

$ sudo apt-get install cpuid

And here is sample output

$ cpuid

.....

Vendor ID: "GenuineIntel"; CPUID level 13

Intel-specific functions:
Version 0001067a:
Type 0 - Original OEM
Family 6 - Pentium Pro
Model 7 - Pentium III/Pentium III Xeon - external L2 cache
Stepping 10
Reserved 4

Extended brand string: "Intel(R) Core(TM)2 Quad CPU    Q8400  @ 2.66GHz"
CLFLUSH instruction cache line size: 8
Initial APIC ID: 2
Hyper threading siblings: 4

Feature flags bfebfbff:
FPU    Floating Point Unit
VME    Virtual 8086 Mode Enhancements
DE     Debugging Extensions
PSE    Page Size Extensions
TSC    Time Stamp Counter
MSR    Model Specific Registers
PAE    Physical Address Extension
MCE    Machine Check Exception
CX8    COMPXCHG8B Instruction
APIC   On-chip Advanced Programmable Interrupt Controller present and enabled
SEP    Fast System Call
MTRR   Memory Type Range Registers
PGE    PTE Global Flag
MCA    Machine Check Architecture
CMOV   Conditional Move and Compare Instructions
FGPAT  Page Attribute Table
PSE-36 36-bit Page Size Extension
CLFSH  CFLUSH instruction
DS     Debug store
ACPI   Thermal Monitor and Clock Ctrl
MMX    MMX instruction set
FXSR   Fast FP/MMX Streaming SIMD Extensions save/restore
SSE    Streaming SIMD Extensions instruction set
SSE2   SSE2 extensions
SS     Self Snoop
HT     Hyper Threading
TM     Thermal monitor
31     reserved

.....

8. inxi

Inxi is a script that uses other programs to generate a well structured easy to read report about various hardware components on the system. Check out the full tutorial on inxi.

$ sudo apt-get install inxi

Print out cpu/processor related information

$ inxi -C
CPU:       Quad core Intel Core2 Quad CPU Q8400 (-MCP-) cache: 2048 KB flags: (lm nx sse sse2 sse3 sse4_1 ssse3 vmx) 
           Clock Speeds: 1: 1998.00 MHz 2: 1998.00 MHz 3: 1998.00 MHz 4: 1998.00 MHz

PgAdmin client SMTPRecipientsRefused: 450, 4.1.8 : Sender address rejected: Domain not found

After the pg installation I tried to reset the pgadmin password but i had this problem:

[error] [pid 12033] mod_wsgi.c(1631): [client SMTPRecipientsRefused: {u’[email protected]’: (450, ‘4.1.8 <[email protected]>: Sender address
rejected: Domain not found’)}

i solved in this way:

vim /usr/lib/python2.7/site-packages/pgadmin4-web/config.py

MAIL_SERVER = ‘localhost’
MAIL_PORT = 25
MAIL_USE_SSL = False
MAIL_USE_TLS = False
MAIL_USERNAME = ”
MAIL_PASSWORD = ”
MAIL_DEBUG = False

# Flask-Security overrides Flask-Mail’s MAIL_DEFAULT_SENDER setting, so
# that should be set as such:
SECURITY_EMAIL_SENDER = ‘no-reply@localhost

 

I changed the SECURITY_EMAIL_SENDER into a my valid email

Restart httpd!