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How SAR command work in LINUX VPS

SAR stands for System Activity Report, as its name suggests command is used to collect, report & save CPU, Memory, and I/O usage in Unix an operating system. The SAR command produces the reports on the fly and can also save the reports in the log files as well.

This article explains how to install and configure the sysstat package (which contains the SAR utility) and explains how to monitor the following Linux VPS performance statistics using SAR.

  • Collective CPU usage.
  • Individual CPU statistics.
  • Run queue and load average data.
  • Swap space used and available.
  • Report SAR data from a specific time.
  • Individual device I/O activities.
  • Memory used and available.
  • Context switch statistics.
  • Network statistics.
  • Overall I/O activities of the system.

How to install SAR in LINUX?

1. Install Sysstat Package

First, make sure the latest version of SAR is available on your system. Install it using any one of the following methods depending on your distribution.

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  • # sudo apt-get install sysstat
  • # yum install sysstat

Note: Make sure to pass the option –enable-install-cron. This does the following automatically for you. If you don’t configure sysstat with this option, you have to do this ugly job yourself manually.

Creates /etc/rc.d/init.d/sysstat

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2. Once installed, verify the SAR version using “SAR -V”

Finally, make sure SAR works. For example, the following gives the system CPU statistics 3 times (with 1 second interval).

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3. Collect the SAR statistics using cron job – sa1 and sa2

/usr/local/lib/sa/sa1

This runs every 10 minutes and collects SAR data for historical reference.

If you want to collect SAR statistics every 5 minutes, change */10 to */5 in the above /etc/cron.d/sysstat file.

This writes the data to /var/log/sa/saXX file. XX is the day of the month. saXX file is a binary file. You cannot view its content by opening it in a text editor.

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/usr/local/lib/sa/sa2

This runs close to midnight (at 23:53) to create the daily summary report of the SAR data.

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sa2 creates /var/log/sa/sarXX file (Note that this is different than the saXX file that is created by sa1). This sarXX file created by sa2 is an ASCII file that you can view in a text editor.

4. Linux 2.6.32-431.e16 – Linux kernel version of the system.

01/18/2017 – The date when the SAR data was collected.

_x86_64_ – The system architecture.

(2 CPU) – Number of CPUs available on this system. On multi-core systems, this indicates the total number of cores.

1.

CPU Usage of ALL CPUs (SAR -u)

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This gives the cumulative real-time CPU usage of all CPUs. “1 5” reports for every 1 second a total of 5 times. Most likely you’ll focus on the last field “%idle” to see the CPU load.

  • SAR -u Displays CPU usage for the current day that was collected until that point.
  • SAR -u 1 5 Displays real time CPU usage every 1 second for 5 times.
  • SAR -u ALL Same as “SAR -u” but displays additional fields.
  • SAR -u ALL 1 5 Same as “SAR -u 1 5” but displays additional fields.
  • SAR -u -f /var/log/sa/sa10 Displays CPU usage for the 10 days of the month from the sa10 file.

2.

CPU Usage of Individual CPU or Core (SAR -P)

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If you have 4 Cores on the machine and would like to see what the individual cores are doing, do the following.

  • “-P ALL” indicates that it should display statistics for ALL the individual Cores.
  • In the following example under “CPU” column 0, 1, 2, and 3 indicates the corresponding CPU core numbers.

3.

Memory Free and Used (SAR -r)

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This reports the memory statistics. “1 5” reports for every 1 second a total of 5 times. Most likely you’ll focus on “kbmemfree” and “kbmemused” for free and used memory.

Following are a few variations:

  • # sar -r
  • # sar -r 1 5
  • # sar -r -f /var/log/sa/sa10

4.

Swap Space Used (SAR -S)

This reports the swap statistics. “1 5” reports for every 1 second a total of 5 times. If the “kbswpused” and “%swpused” are at 0, then your system is not swapping.

Following are a few variations:

  • # sar -S
  • # sar -S 1 5
  • # sar -S -f /var/log/sa/sa10

5.

Overall I/O Activities (SAR -b)

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This reports I/O statistics. “1 5” reports for every 1 second a total of 5 times.

The following fields are displays in the example below:

tps –

Transactions per second (this includes both read and write).

rtps –

Read transactions per second.

wtps –

Write transactions per second.

bread/s –

Bytes read per second.

bwrtn/s

Bytes written per second.

Following are a few variations:

  • # sar -b
  • # sar -b 1 5
  • # sar -b -f /var/log/sa/sa10

6.

Individual Block Device I/O Activities (SAR -d)

To identify the activities by the individual block devices (i.e a specific mount point, LUN, or partition), use “SAR -d”

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Following are a few variations:

  • # sar -d
  • # sar -d 1 1
  • # sar -d -f /var/log/sa/sa10
  • # sar -p -d

7.

Report network statistics (SAR -n)

This reports various network statistics. For example, the number of packets received (transmitted) through the network card, statistics of packet failure, etc., “1 5” reports for every 1 second a total of 5 times.

  • # sar -n KEYWORD

KEYWORD can be one of the following:

  • # sar -n DEV 1 1

DEV –

Displays network devices vital statistics for eth0, eth1, etc.

EDEV –

Display network device failure statistics.

NFS –

Displays NFS client activities.

NFSD –

Displays NFS server activities.

SOCK –

Displays sockets in use for IPv4.

IP –

Displays IPv4 network traffic.

EIP –

Displays IPv4 network errors.

ICMP –

Displays ICMPv4 network traffic.

ICMP –

Displays ICMPv4 network errors.

  • Display context switch per second (SAR -w).

This reports the total number of processes created per second, and the total number of context switches per second. “1 5” reports for every 1 second a total of 5 times.

  • # sar -w 1 5

8.

Reports run queue and load average (SAR -q)

This reports the run queue size and loads an average of last 1 minute, 5 minutes, and 15 minutes. “1 5” reports for every 1 second a total of 5 times.

  • # sar -q 1 5

By using the SAR command we can find out the performance status of the server.

Conclusion

Still confused how SAR command work in LINUX VPS? Contact Ideastack now!

Frequently Asked Questions

Q1. What is sar command used for?

The sar command can be used to keep track of a variety of system resources on a Linux system, including CPU and memory usage, file system performance, I/O device consumption, network monitoring, disk usage, process and thread allocation, battery life, plug-and-play device performance, and more.

Q2. How does sar collect data?

Using SAR, gathering, and reporting resource data requires two steps. The first step is to collect test data and save it as a binary file. In the second step, extract the desired data into a text (.txt) report.

Q3. Where are sar files stored?

The term “sar” refers to “system activity report,” and it can be configured to automatically generate daily reports, display current performance, or deliver reports based on log files kept in the /var/log/sa (or /var/log/sysstat) folder on your system.

How to change process priority using Linux Nice and Renice

In a Linux system, there are hundreds of processes, that are continuously running different tasks. Linux Kernel does a fantastic job of mediating between these processes and allotting CPU to these processes.

Every running process in Linux has a priority assigned to it. We can change the process priority using nice and renice utility.

With the help of the Nice command in Linux, you can set process priority. If you give a process a higher priority, then Kernel will allocate more CPU time to that process.

The Nice command will launch a process with a user-defined scheduling priority. Renice command will modify the scheduling priority of a running process. Linux Kernel schedules the process and allocates CPU time accordingly for each of them.

The process scheduling priority range is from -20 to 19. We call this a nice value.

A nice value of -20 represents the highest priority, and a nice value of 19 represents the least priority for a process.

Follow the below process to increase the priority of any process:

1.

Login into your Linux system via user name and password, and enter the # top command.

Cheap Linux VPS 1

After hitting enter you will get output like the above screen, in that NI means Nice Value of a particular process.

2.

We can set the NI value of any process or command in 2 ways.

a)

In the output of the # top command, just enter ” r ”, and we get the screen like the one below:

By default when a program is launched in Linux, it gets launched with the priority of ‘0’. However, you can change the priority of your service yourself.

Cheap Linux VPS 2.a1

Simply just put the PID of any process or the PID of that process in which you want to increase the priority. Hit enter after putting PID.

Cheap Linux VPS 2.a2

It will ask for Renice value, see the above screen. put the value priority range from -20 to 19. We call this a nice value. A nice value of -20 represents the highest priority, and a nice value of 19 represents the least priority for a process.

After putting the renice value, the process priority will change according to the NI value.

Check the NI column after purring renice value of any process, see below screen.

Cheap Linux VPS 2.a3

In the above screen, the PID of kthreadd is 2 and its nice value has been changed to -10, which means now it has higher priority among then all processes, which is running under a Linux system.

We can also set the NI nice value of any process like httpd, java, MySQL, FTP, or sshd to make that service perform fast.

b)

We can set NI via another way, by using the simple below command.

After the top command, do the below step to increase the performance of any service, or process.

# nice -10 httpd

The above command will set the NI value of the httpd service to 10, which means it has lower priority among all the running processes under the Linux system.

# nice –10 httpd

The above command will set the NI value of the httpd service to -10, which means it has the highest priority, we can increase this value to -20, A nice value of -20 represents the highest priority.

Conclusion

Still, confused about how to change process priority using Linux nice and renice? Contact Ideastack now.

Frequently Asked Questions

Q1. What is nice in Linux?

Nice is a program that may be found on Unix and Unix-like operating systems like Linux. It corresponds straight to the same-named kernel call. Nice is used to call a utility or shell script with a specific CPU priority, allowing the process to receive more or less CPU time than other processes.

Q2. What is nice value?

The process’s priority is determined by the value. The process is considered to be “nicer” than other processes the higher the value, the lower the priority. On Linux workstations, the nice value by default is set to 0. The size of the process in memory is shown in the SZ field.

Q3. What is nice and renice in Linux?

The nice command sets the priority of a Linux process before it runs. It is not possible to change the priority after it has been established using the nice command. In this case, you can use the renice command. With the renice command, the priority of an active process can be modified.

The two avenues in Web hosting – Dedicated and Shared hosting

If you select a small business through the internet, a web hosting company is normally a simple way to progress with various goals and the best outcomes. However, there is absolutely nothing as easy as it seems to be. There are many offered choices in the site hosting so that you could discover the best one that fits your small business requirements and needs.

Therefore if you face any difficulty with possessing your server or maybe a shared one, it might be suitable to state you might have landed on the terrific discussion of dedicated hosting vs. shared hosting. Progression of the two leading pathways that you might treat for the organization.

The website hosting is a kind of web hosting in which you spend money with a third-party services provider for your joint website server that you hand out to the other web servers. The transaction of clinking coins is regular monthly as well as almost preventing every other hardware purchase cost. Right here, your issue area regarding your site is simply restricted by choosing within the website page.

The security is too handled via the vendor. This kind of web hosting is the most affordable with all of the self-proclaimed web host providers kinds on the market. Owning numerous benefits, you will also find certain drawbacks that you have to tackle in all types of hosting.

Since you are with a website server that is found through several additional sites you may want to reveal your IP address which may be regarded as a danger. Additionally, you may a limitation in data transfer as well as disk space. Right here, you will be usually influenced by various other people for getting some vital tasks done, depending on your website.

Website hosting

When operating in contrast, the dedicated server web host lets you expertise and the means to access a total website server this is not shared by anyone. Right here, you might have total independence to choose as well as personalize the operating system, hardware, growth, setting up of functions, and so on.

This also has a quick reply pace that prevents any specific visitors from obtaining increased from the less quick reply within the website and also has simply no limits on throughput.

The basic safety and comfort during this kind of web hosting are likewise more. With this kind you can be the boss, in spite of this whenever the amenities are usually your efforts and cash needed is not at all much less.

Therefore, with the advantages and disadvantages of the different types of web host providers, you can possibly choose the one which is ideal for your company. For those who have small businesses in their areas, they do not want an enormous bandwidth than simply a shared web hosting capable of doing your profession. But when you have obtained a big business full of traffic rates specialists who log in and spend the price required, it is recommended to obtain a dedicated server host.

Conclusion

For more information visit Ideastack.

Web server

Frequently Asked Questions

Q1. What is the difference between web hosting and web server?

A computer that saves and uploads your website to the internet is known as a web server. Web servers are used by a business or service referred to as a “web host” to store and display your website.

Q2. How many types of web hosting are there?

There are 4 types of web hosting: shared, dedicated, VPS, and cloud. Shared hosting places your website on the same server as other websites. Dedicated hosting allows you to have your own own server for your website. VPS, or virtual private server, is comparable to dedicated hosting but does not rely on a physical server. Cloud hosting hosts your website using cloud resources.

Q3. How is a website hosted?

A website is hosted on a web server, which is a dedicated computer that saves your website’s files and transmits them to the internet when a user visits your website’s URL and requests them.

R1Soft Backup Manager

What is R1Soft?

R1Soft Server Backup Manager is a near-continuous backup application for Windows and Linux servers. R1Soft allows for the backup of both physical and virtual devices. The software provides user scheduled continuous disk-based online backups for one or more Windows or Linux servers. Each time a user scheduled backup is perform.

Individual files inside of a disk image can be restored to their original location or an alternate computer.

In the R1Soft Server panel, we can add up to the total size of the HDD available in the R1Soft backup manager.

In that panel, it is very easy to add Windows or Linux machines, just see the below:

1.

You can access all of the functions you need to manage your users by clicking Users in the Main menu which is under the Setting option.

R1Soft 1

2.

We can schedule back as per our requirement, in that panel we can set an automatic backup generator, this panel includes Policy. Once the backup is done successfully and we want to take again backup of the same machine, this panel has an incremental backup process.

R1Soft 2

3.

Just click on backup now, and it will start incremental backup for that machine.

R1Soft 3

What is the advantage of R1Soft Backup Manager?

  • This panel starts taking backups of a particular machine block by block, either its Linux or Windows.
  • With the help of this R1Soft Backup manager, we can restore a single file from the Recovery point to the destination point where you want to restore.
  • We can download a particular file or folder which is already backup was taken up or which is present in the recovery point.
  • It provides better security for data.
  • We can restore the whole machine to a new machine with the same data as per your requirement.
  • It will generate a new machine with the same data, which was already in the Old machine.
  • It's like a true copy of the old machine.
  • It provides the log for all machines when you get any error while connecting to that machine, which you want to take a backup, and it provide the whole log of errors when the machine did not connect with Agent.
  • If any running process goes canceled, it also provides the reason for cancellation, a log will appear in the Log option.

Why should we use R1Soft Backup Manager?

R1Soft takes a slightly different approach to server backup than most traditional backup companies. While traditional, incremental backup products allow you to backup your data at the file level, Server Backup Manager (SBM) enables you to perform backups at the block level.

1. Easy-to-use web-based control panel

  • Bare-Metal Restore (BMR) for full server restores.
  • Support for both Linux and Windows.
  • 7 daily recovery points & SQL protection.

2. File Include/Exclude option available

The best thing about R1Soft Backup Manager is it has the option of file include/exclude. It is very helpful when we start tacking back up the machine.

If the HDD of the R1Soft Backup Manager is low then we can take the only backup of our important files also.

3. Fewer performance issues

One major advantage of bypassing the file system is that there is no penalty on backup performance for having a large number of files. The backup application never looks at files and doesn’t care how many files there are on a server.

Block-level backups start by taking a snapshot of the live running volume. The block-level data is then read from the snapshot, rather than the actual disk. This allows the backup to run in harmony with your file system, rather than taxing your servers and causing performance issues for hours on end.

4. Easy file restores

While not every block-level backup solution could do this, our block-level technology can read files and file attributes from raw disk blocks in a platform-independent fashion. That means that R1Soft’s Server Backup Manager doesn’t have to rely on the operating system when it’s reading the data.

Not only does this allow you to backup both Windows and Linux servers, but it also allows you to perform cross-platform file restores. Making your restores O.S. agnostic gives you the flexibility to restore files out of block-based backup done on a Linux server to a Windows server and visa-versa.

Other applications require that you set up your NFS or CIFS share for the backup application to store and read backup data from. R1Soft has its network protocol for moving the files and blocking data so you don’t have to configure a network file system.

5. Faster and more efficient

The file system is responsible for keeping track of the tree or hierarchy of files. In doing so, it stores files in neat little fixed-size blocks on the disk. Unfortunately, files can be located on blocks that are scattered all across the disk.

Because of this, backup applications that read data at the file level are forced to jump all around the disk and traverse the directory tree just to find all of the files eligible for backup. This tends to be a very fragmented, convoluted process that causes the disk to spend as much time, if not more, searching for the correct information instead of reading the data.

Voiding that unnecessary search party goes a long way in shortening your backup window and making the whole backup process that much more predictable.

6. Backup your data securely with crucial

Dedicated server and VPS customers of crucial can back up their data safely and securely with R1Soft Backups.

R1Soft Backup works by taking a full server backup, then incremental or ‘changed-file’ backups each night, thus creating 7 daily recovery points. The advantage of R1Soft Backup over the typical FTP or image backup is the ability to login to the R1Soft Backup control panel via a web interface and browse & restore individual files or folders.

Conclusion

For more information visit Ideastack.

Frequently Asked Questions

Q1. How does R1Soft backup work?

Our method, like traditional backups, begins with a comprehensive snapshot of your data. The similarities, however, end there. Server Backup Manager continuously tracks changes to your data after the initial duplicate is generated and only saves the information that has changed.

Q2. What does a backup manager do?

A backup manager is an application that plans, manages, and performs data backup procedures on a computer, server, or network device. It is a client/server integrated application that extracts backup data copies from a source computer or IT environment to a remote storage facility.

DDOS Protection – How to protect your business from DDoS attacks

The DDoS security alludes to a progression of activities that endeavor or attempt to determine the aforementioned issues. It additionally shields the system from future DDoS attacks.

So imagine a scenario in which the system is being attacked by DDoS is it important to benefit from the security. The direct response for this inquiry would be, “Yes, it is fundamental and quick to get DDoS Protection.” This can be acknowledged if the dangers and conceivable harms of DDoS attacks have been uncovered.

DDoS attacks can lethally harm an entire system, not only a solitary PC. This can make opening records to a great degree and strangely moderate. The attack is likewise equipped for wearing the limit of the preparation of a switch and even assets for the system stack.

The most and most seasoned way or style of a DDoS attack is the way of sending a lot of email messages to a solitary beneficiary. Thus, this procedure fills a colossal space in the PC’s hard plate drive. This style is really an extremely exemplary one yet at the same time endures in the business.

Besides, when a DDoS attack happens, it generally softens a ton of machines up the World Wide Web. Subsequently, this prompts transfer speed weakness or breakdown.

DDOS security

The most widely recognized destinations of the DDoS attacks incorporate the Internet, File Sharing sites and administration suppliers and even Domain Names Services.

Additionally, there is a pattern saw by specialists, which recommends that DDoS attacks, for the most part, happen fantastically amid high deals periods. With this pattern, it is not just the business powers that are being attacked, however the customers also.

In any case, these system issues being experienced can be determined strategically and even deliberately through the use of DDoS insurance frameworks. Yes, without a doubt, it is valid. Online and disconnected from the net openness issues can be determined as needs are. This DDoS protection is really being utilized by a considerable measure of site proprietors in the web and organizations.

Conclusion

The DDoS protection by Ideastack guarantees a considerable measure to its clients, it accompanies a moderately aggressive expense. While the expense can be very high for most organizations and site proprietors, this can be dealt with as a shrewd venture to guarantee the most extreme efficiency of the organization. Probably the most critical elements of the DDoS Protection include crisis bundles and firewall choices.

Frequently Asked Questions

Q1. Why DDoS protection is important?

DDoS protection services help businesses maintain the availability of their websites and applications on by keeping track of traffic and preventing distributed denial of service attacks. Organizations may better prepare for the impending threat of DDoS attacks with the aid of DDoS Protection.

Q2. What are the methods for DDoS attacks?

DoS attacks can be classified into two types: flooding services and crashing services. Flood attacks happen when the system receives too much traffic for the server to buffer, causing it to slow down and eventually shut down. Buffer overflow attacks, the most frequent DoS attack, are examples of well-known flood attacks.