client vs server performance.

Aug 18, 2014
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Hello,
I am sizing a PBS server.
I am doing some backup tests and I would like to know if it is the client that must have good performance or the server?
Is backup speed related to client performance or server performance?

What does the maximal backup upload speed depend on?

When backing up a VM, what is done on the client side and what is done on the server side?

Cordialy
 
The network between the server and client is an obvious thing. The storage on the PBS is another factor. Since backups are stored in many chunks, the data is spread out randomly. Then you might have multiple clients accessing the data and some maintenance tasks at the same time. Therefore, random IO is something to look out for. This is the reason why we recommend to use SSDs if possible. They provide much better random IO performance than HDDs.

If you back up a running VM from a Proxmox VE server to a PBS, the overall backup performance is also important (network, storage) because of how Proxmox VE backs them up. During the backups, Proxmox VE will intercept write operations from the VM, will check if that part of the disk is already backed up, and if not, will first back up the part of the disk image that the VM want to write to. Once that part is backed up, the write operation can proceed. It is doing this to make sure, that the disk is backed up as it was at the time the backup started.
 
Just to add: Stuff like encryption, compression, hashing and so on is done on the client so you don't have to trust the PBS hoster and only need to upload as less data as possible.
 
Just to add: Stuff like encryption, compression, hashing and so on is done on the client so you don't have to trust the PBS hoster and only need to upload as less data as possible.
except when done on the server like for example for the verification