What file systems are used in very large storages?

Question

Parsing

Actually, the question is in the title. In particular, I am interested in which file systems are used by cloud storages (the same Dropbox, etc.), file hosting such as Depositefiles and other projects where it is critical to store very large amounts of data, and at the same time store it securely. On one well-known forum, everything that is not ZFS is extremely dismissive and almost squeamish: supposedly, only ZFS is able to reliably perform the function of storing data, and all these ext4 and others are only suitable for routers. So I became interested - but really, what FS are used on an industrial scale?

Answer 1

You need to write a solution for a specific task, if you google it right as in the question and add a PL, the search engine will give you examples.
Everything else (a specific decision) is done for money, or for your time (with your hands / head)

Answer 2

for local storage zfs (instead of hard/soft raid)/xfs/ext4, for distributed ceph/glusterfs/gfs2

Answer 3

Cepth , for example. ZFS is no good here...

Answer 4

Various. ZFS, of course, is wonderful, but it also has a number of disadvantages. In many cases, normal redundancy is sufficient. For example, you can read this article:
https://www.backblaze.com/blog/vault-cloud-storage...
There they write that they have ext4 on separate disks, but above this they have additional logic that breaks files into pieces and distributes them across volume disks, which consist of disks located in different racks, plus writes parity data.