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Slow Samba Share Backups

I have an issue, when backing up a File Share mounted under Samba on a Media Server at a different georgraphic region, using autofs (automounter).

The backup starts fine. Runs very well, and then just sits there until some action is taken.

If I cancel, and rerun the backup, give or take a few Kb, it hangs around the same point. It is an accelerator backup. 1 backup is around 450Gb, the other is 1.1Tb. Other backups from the same area that are between 200, and 300Gb work without any issues. There are lots of small files in all backups.

The only things that seems to work, is to restart the autofs service - systemctl restart autofs.

However, this works for a short time, and unless I restart autofs it will sit there indefinitely. I have to do this roughly every 10 minutes until the backup completes. This happens on Full, and Diff Incremental. 

NBU - 8.1.1, Samba - 4.8.3.

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3 Replies

Re: Slow Samba Share Backups

Identify the file/folder causing backup to hang. Then try to exclude it from the backup or resolve root cause. My guess is that Windows/Linux won't be able to acess file/folder causing backup to hang.

Technote below provide guidance on how to identify file or folder causing backup to hang using the bpbkar debug log.

Pls see: https://www.veritas.com/support/en_US/article.100003560

 

Re: Slow Samba Share Backups

Thanks, but it is not a folder/file issue, as the rerun(s) stop at a different file every time. 

And if the backup, or rerun is allowed to carry on with manual intervention it passes the file that it originally stopped at. No errors in backup log saying anything about a bad file. No errors in any logs.

It's more of a timeout hang than anything, and only occurs once 4 other streams that run alongside finish, and the amout of data being sent drops. This link used to have WAN optimization, but that was disabled, and ever since this issue has occured. The backup can hang at anywhere between 75%, and 85%, and as I mentioned, always on a different file/folder being backed up.

As of this weekends Full, I intend to break the backups down into multiple streams to see if that helps, but the problem with that is, the majority of the data on the 2 backups is contained in 1 folder. 

Re: Slow Samba Share Backups

OK - I see. Thanks for the update.

I am afraid you have to look at the autofs/samba side to solve the issue.

I did a quick google and there seems to be other people having the same issue as you with Samba and flaky VPN connections (VPN or WAN - same challenges).

If traffic from passes a firewall make sure to setup TCP keepalive

https://www.veritas.com/content/support/en_US/article.100028680.html