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Hey guys and welcome back. So what I want to talk to you about in this skill right here

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is all around the concepts of backups. Now when we happen to discuss the idea of raids

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in a previous skill we understood we could actually survive some type of failure within the system.

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This is what the redundancy actually gave us but here is the deal. Raid is not a substitute for a

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good backup solution. Indeed if you happen to have a raid array within your office maybe one of the

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physical disk breaks and you are okay because the raid array can actually rebuild that data. However

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what would happen if your actual whole entire office went on fire then that raid array within

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that single location would be destroyed and all of your data would be gone. Instead we want to be

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able to have the ability to do some robust backing up. So this is really very very important in fact

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I would say it is critical to ensure your data has this backup otherwise it could be lost forever.

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This could perhaps be customer data it could be valuable data just to keep your system up and

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running a million reasons why you want to have this data backed up. So what I want to do to

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introduce this skill is to go through some of the basics around backing up before we actually walk

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through the different tools that we can use to do such a thing. So the question would be is what

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exactly should you back up because think about it does it make sense to back up absolutely everything

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all the time. The reality is this is unlikely to be the case instead you would very likely want to be

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selective about what it is you're backing up that means that you only want to back up things which

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are important to you that way you are not just needlessly using update of storage instead everything

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you back up has value in of itself. So let's discuss some of the directories that we should

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actually think about when we're talking about our backups. Now one of the first directories that you

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should consider backing up is the home directory. The reason being is that very often given that

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this is your home directory this is going to contain many many files which are valuable to you as the

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user. Now of course if you only have frivolous information within your home directory you could

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in fact skip this directory but the reality is is that this is unlikely to be the case you're

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very very more likely indeed to have valuable information stored within this directory so

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certainly the home directory should be a candidate for consideration when backing up. Now the next

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directory is the user directory now this can be a little bit of a contentious one some people

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feel that it is not worth backing up the user directory whereby others absolutely swear by it.

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Now the reason why some people would prefer not to actually back up this particular directory

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is that the contents of this directory are not likely to change instead this is going to be

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stuff that you get from your package manager so if you happen to be on debian and you install

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software we're using the apt program or the apt package manager should I say. The argument is

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is that it's not so difficult on a new system to simply use that package manager again to pull

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those same files that would populate within the user directory so there's not much changes going on

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here it's not so difficult to get a working replica of this directory if you so need it so long as you

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just remember what it is you have installed on what you need now this last part here is exactly why you

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may consider actually backing up this directory because even though you could use something like

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say the apt package manager or say for example yum if you're on retat what if you can't remember

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all of the software that you had on your system sure if you keep a detailed list of everything

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that you have actually installed you could use these package managers to repopulate this user

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directory but if you spend the time just to back up this directory then you don't have to worry about

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such a thing you just copy it over and everything will be there again now the next directory would be

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the etsy directory now this directory has system-wide configuration files and because of this nature

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this directory is frequently updated and is changing therefore it does make sense to take a nice

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snapshot of this directory in a current working state and include it in your backups as opposed

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to again trying to recreate this directory after the fact so like i say whether you're installing

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new software or you happen to be making changes to your user account or your group accounts all of

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this basic day-to-day administration can alter this file and when something is altered regularly

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this can be a signal for you that it is something that you should be considering backing up now the

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next one i want to talk to you about is the boot directory now within this directory this is where

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you're going to find the kernel now if you happen to be planning to maybe install a new kernel then

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is a good idea to ultimately back up this kernel i.e it is a good idea to make a copy of this directory

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right here the boot directory where the kernel will actually live that means if you happen to have

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some type of error you can quickly roll back and get everything working once again next we have the

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bin directory where we keep our binaries now this is one of the decisions that you should actually tie

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to the user directory if you choose to back up user then it does make sense to also back up the

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bin directory simply puts what you happen to be backing up from the user directory will often rely

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on the data that you have within your bin directory so you would like to have some type of parity between

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the two if you back up one make sense to back up the other exact same logic with respect to the

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sbin directory if we're backing up user the same logic does apply some of the system software that

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has been installed in this directory is going to rely on information found in the sbin directory so

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don't give yourself unnecessary headaches by backing up this and not having the required files you

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need from here if you back up one good idea to back up the other just like with the bin directory

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next we have the opt directory we know the opt directory is going to store our add on application

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information so realistically if you happen to rely upon a lot of third party software then the

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information within the opt directory will be valuable to you thus it would make sense to indeed

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back up this directory the reality is though very often people do not choose to back up this

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directory again there is no absolute right or wrong answer here this is something where you

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have to use your own judgment now we know the var directory is going to have a lot of changes

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within it ie this would be something that is difficult to recreate after the fact if we happen

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to lose this data say for example we maybe have the var backups directory if we're on a debian

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system this is going to contain at package status backups and additional system files

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similarly within the var directory we could have our var lib folder this is going to contain

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variable information about the state of our applications and our system also we're going to

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have var log this is going to contain system and application logging information so again this

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could be something that you happen to find very very valuable you want to keep as well as we could

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have var mail this would contain all of the local user mail on the system so this is something you

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would want to retain again this would be within the var directory and we would also have var

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www if you happen to be say for example running a web server the web content from that server you

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could find within here so again within the var directory this is something to consider so it

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may seem like a home run a var directory is something we absolutely would always want to back

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up but this really again is not the case i would say in my opinion it is very likely you would want

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to back up this particular directory or perhaps some of the particular subdirectories within the

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var directory but again it really does depend on your assessment of the importance of what is within

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this particular directory maybe you happen to not be caring about the log file so much

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because maybe you're installing a generic desktop computer however if you happen to be on say for

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example a server within the system whereby you have tons and tons and tons of logs which are

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very very important well it does make sense that that var directory would be included within your

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backup strategy now we also have the lib directory this is again something to consider if you happen

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to back up that user directory simply put because the operating system libraries will be installed

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within this structure in fact it may also actually be within lib 64 depending on the system now these

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are some of the locations we should think about with respect to our backups what abouts particular

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directories or file systems that you should not back up well again there is never an absolute hard

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rule here but this is a general guideline but really information that is not stored on your

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actual hard disk such as maybe say a removable usb stick this is not necessarily something you would

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have to back up on your local system similarly information that contains temporary data think

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about it why would you want to back up data which by design is supposed to be temporary so certain

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locations such as the dev directory or the media directory or the mount directory these are directories

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and file systems that typically do not need to be backed up also we know we have the proc directory

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and the sys directory which are virtual file systems which ultimately are generated within memory

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this is transient data relating to things like currently running processes on our system again

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this is not information you would want to back up the only time you would actually want to back up

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this type of data would be if you wanted to perform some type of forensic investigation into what was

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happening on a device at a particular time again this is a very specialized use case and not typical

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within a enterprise backup strategy similarly within the var directory we definitely have some

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data we would want to back up but actually we probably wouldn't want to back up the var temp

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folder because again the data here is specifically designed to be temporary it's not going to have

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any value to us in the long term so these are just some of the things that we have to consider with

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respect to the location of what it is we should back up but we still have more information to

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look at before we go about implementing our backup strategy so what other factors do we have to

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consider well that's what we're talking about in the very next nuggets i hope this has been

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informative for you and i'd like to thank you for viewing