Slow backup - where's the bottleneck?

I’m running client and server on the same windows 7 machine and backing up to a usb3 hard drive. Resource monitor reports that urbackup is reading about 15MB/s from my hard drive (an HDD) and writing the same amount to my usb drive.
A backup of a few hundred gigabytes takes several hours. I can live with that but I wondered what the bottleneck was.
I’m currently doing an incremental backup. Both drives show ‘active time’ almost always well below 50%. My CPU is almost idle, except one core which never goes above 50%. I have a lot of RAM but urbackup is using at most a couple of dozen megabytes. No resource seems anywhere near saturated.
This is partly curiosity, but I would really appreciate it if someone with a bit more knowledge of computer IO would give me a hint what’s going on here. Are the drives waiting for each other and the processor? I would be happy for urbackup to read the drive more continuously and use some more RAM as a cache.

While I have not used this program for as long as some of the other members, or used a server-client on the same machine, I have noticed one thing.

When we backed up our file servers, it would hang up - even incrementals that only added one gigabyte were taking upwards of eight hours to complete while the full backups only took about at most two hours. During this time we were not just backing up over-night, but also testing load balancing and bandwidth during our daytime hours. Long story short, it seems as if the program will halt if there is an open file, and will not proceed until that file is closed.

So, say that Mary Sue left her computer on over-night with a word document open, her backup would have been halted until the file was closed, or the backup timed out - whichever came first. I am not entirely sure how the program works, but it made the most sense - especially with it being our file servers.

To answer your other question: I am not entirely sure how computer hardware logistics work, but with you talking about read/write from hard disk to hard disk. It should only take what it can handle; if your hard disk can write at 50MB/s, and the one you are writing to can only read 25MB/s, then your bottleneck would be there at the one reading the data - and vice versa, resulting in the one writing the data.


Extra tid-bit I meant to add: Double check your server settings, under the (Settings -> Advanced) tab and down towards the bottom you should see

Run backups with background priority on Windows: [X]

For me, that was ticked on by default; I would double-check to make sure that option was un-ticked to prevent it from being just a background application (may speed things up for you), and to double check this under your (Settings -> Server) tab.

Total max backup speed for local network: [ - ]MBit/s

(the hyphen there should be default, and should state that you want no limit for the transmission speed)

After that I would just check your settings under (Settings -> Advanced), the backup transfer modes: Block Differences - Hashed -> Hashed -> Raw (quickest to slowest speeds).

I hope I got all that right. :smile:

Interesting. But it wasn’t on an open file and both the source and destination disks showed low active time.

Well, the only thing that I can think of at that point is the setting on the server side or that your hardware was intentionally (or unintentionally) throttled - or possibly worn, if your computer has been around for a while. If those options are all set right, then I don’t really know what to tell you because the disks should use all their resources to read and write as fast as possible.

Hopefully another member who knows more about this could drop in and assist you further, also it would help if we knew exactly what you were working with.