Once again, one of the very basic question asked in the interviews, What is the difference between Hard links and Soft links. You can explain few basic things, but emphasizing on internals about the linux filesystem, is something which can impress the interviewer.
To secure your machine, there are hundred different things you can do, but the most important thing is to know what's happening on your Machine. In that getting the alerts as soon as someone login is one of very important and must thing to do.
So, to do the same thing, you can go with two approaches:
Inode, short form of Index Node is what the whole Linux filesystem is laid on. Anything which resides in the filesystem is represented by Inodes. Just take an example of an old school library which still works with a register having information about their books and their location, like which cabinet and which row, which books resides and who is the author of that book. In this case, the line specific to one book is Inode. In the same way Inodes stores objects, which we will study in detail below.
So, in the linux system, the filesystem mainly consists of two parts, first is the metadata and the second part is the data itself. Metadata, in other words is the data about the data. Inodes takes care of the metadata part in the filesystem.
When you create a file, it's stored in different blocks/locations of the filesystem/disk depending upon the size of the file. Though you don't need to know the physical location of the disk in normal scenarios, but you might need it in things like, to understand the filesystem layout and how file is stored on the filesystem or to do performance tests.
Finding the physical location of the file can be achieved by following commands:
When it come to optimization of a site or web-server, ETAGs and Expiry headers are the two main things you should be looking at. ETAGs and Expiry headers will be used to understand by the client whether to fetch the latest file or not, but still there is a difference between these two and are used at different scenarios.