Image Backup hanging at 100%

general discussion
1

Hello!

First i’d like to say i’m very pleased with what UrBackup has to offer at the moment. It’s very simple and reliable; it basically does exactly what I need and what pricey closed source software could not achieve. Thank you very much :D

However, i’m a bit concerned with the time taken for full image backups. They get to 100% very quick but then hang for a very long time (+10h)…

WIN2K8-T43 	Full image backup 	2014-04-19 21:27 	635 min 	20.66 GB

Since my backup is on a slow NAS, I use a 500GB USB drive as a buffer which drastically improved the image backup speed (reaching 100%). From that point, it hangs for hours and from my observation it seems to be the process from which UrBackup copies the temporary image file to the network storage. It’s very slow. A normal file transfer from that same drive to the NAS average 20Mb/s so I dont understand why its so long to copy!?

Also, once its done, it still displays “No recent backup” for image backup even if the process as ended for a while already.

Computer name Last seen         Last file backup   Last image backup   File backup status   Image backup status
WIN2K8-T43    2014-04-19 21:13  2014-04-19 14:52   2014-04-20 08:01    Ok                   No recent backup

Could you please help me fix this?

2

Assuming you use it on Windows I don’t know if there are any tuning options. The VHD writing is done in small blocks (512 bytes) which could be a problem if the file sharing with the NAS doesn’t buffer. On Linux with samba I would e.g. look at TCP_NODELAY etc.

You could also try 1.4. There the image compression causes a) A larger write block size (2MB) and b) less stuff to be written (i.e. transferred to the NAS).

3

I disabled the “Temporary files as image backup buffer” for full image and it was taking the same amount of time but would not hang at 100%. I switched to 1.4 and the performance greatly improved! (unless turning back “Temporary files as image backup buffer”). Overall, compression was not a major factor in improving performance; maybe 20% faster by disabling but the space gain is worth the extra time.

So I believe what you say about the NAS buffer to be accurate. My server is indeed a windows machine (2008 server) and writes to a shared drive on my network which is a Samba share (3TB USB attached on a RT-N56 using optware). So that TCP_NODELAY has to be configured on the source or target to be effective? (my guess is target!)