#1 2020-06-15 13:17:40

mbutsko
Member
Registered: 2020-05-16
Posts: 8

Can two XSIbackup instances use the same repository simultaneously?

May be a silly question.

Is it safe to have two hosts running backups at the same time and point them to the same repository but different --subfolder?

It had just occurred to me that there could be some data conflicts if one XSI is not aware of the other, or am I wrong?

Thank you!

Offline

#2 2020-06-15 13:42:23

admin
Administrator
Registered: 2017-04-21
Posts: 1,363

Re: Can two XSIbackup instances use the same repository simultaneously?

Of course it's not a silly question. It is probably the most interesting question to place about (c)XSIBackup-DC, as concurrency allows to use it at a datacenter level in an extremely efficient way. That's what its aim is.

Yes, concurrency is managed through .lock files. Nonetheless, even if there was no lock mechanism, the possibility that the same unique block is being written at the same time from two or more hosts is negligible.

Still obviously some kind of locking mechanism is required. In the future it will be superseeded by semaphores to allow many hosts writting at the same time while still optimizing lock times.

The biggest concern is the .blocklog file, the main manifest where unique blocks are registered, but that may be rebuilt at any time by a --repair argument. Thus, just as long as your local manifests (inside every VM folder) and your blocks are O.K., you can always rebuild the repository.

Offline

#3 2020-06-15 13:50:12

mbutsko
Member
Registered: 2020-05-16
Posts: 8

Re: Can two XSIbackup instances use the same repository simultaneously?

Ah, I do remember reading about the lock files and rebuilding via the --repair argument now that you mention it! Cool, thank you for the fast information as always.

Offline

Board footer