Synthetic full backup creation fails over 1Mbps Fibre link?

[DavidDarts]

Hi Everyone,

I am performing a 'full synthetic backup' to a NAS over a 1Mbps fibre optic link between two buildings - which are separated by about 200 meters.

When performing the backup I receive the error message shown below -



The vbk file in question is about 2.5 Terabytes in size and I suspect that there is a data buffering issue at hand. The last three backup attempts have all failed after approximately 10 hours, and ten minutes.

The NAS that I am using does not currently have NIC teaming enabled, and I am thinking that this feature may help resolve the issue.

I have few of questions, 1). Is it reasonable to perform this kind of backup on such a large file over a 1Mbps fibre optic link?, 2). If performing the backup on said link is reasonable what is the most likely cause of this error message?, 3). If it is not reasonable to perform this backup over the link what settings should I be using in my backup?

Any help here will be greatly appreciated.

Kind Regards,

David

[Vitaliy S.]

Hi David,

1. If your link is stable, then it should be fine. BTW, how did you present this NAS box to your backup server? Via Windows Server or CIFS share?
2. Connection drop.
3. Seems like you're using CIFS shares, which can be unstable. In order to resolve that issue, use Windows or Linux based repositories.

Thanks!

[alanbolte]

A failure at the 10 hour mark may indicate a Kerberos timeout. There may be a workaround in SAMBA settings or some GPO, but the only approach I've actually seen to be successful (aside from increasing performance or switching away from CIFS) is to use non-domain authentication on the NAS.

[alanbolte]

I should probably also note that without switching to a complete Windows or Linux-based repository, you could specify a Windows server on the other side of the connection as a gateway for the share. That way, only incremental data goes across the slow line, and processing of that data into a full backup file can be restricted to the fast LAN connection between the gateway and the NAS.

Also... 2.5 TB over a 1mbit/s line? Wouldn't a full backup take the better part of a year at that speed? How did you manage to create the previous backups in the first place?

[DavidDarts]

Hi All,

Thank you very much for your inputs. My apologies concerning the original post (as pointed out by alanbolte) the link speed is actually 1Gbps rather than 1Mbps.

Kind Regards,

David

[DavidDarts]

I am wondering if anyone can explain the various Windows Repositories available, and the Pro's and Con's of each one? I figure that I could make the NAS an iSCSI target, however I would then need a functioning Server to connect to the data. If I use a Windows Repository does this mean that I will always need a Server to connect to the data?

[Vitaliy S.]

The major difference between CIFS and server (Windows/Linux) based repositories is the location of our data mover services. If you deploy Windows repository and have your NAS attached to this server, all required services will be deployed in this Windows server and all the traffic for synthetic backup will be kept locally. In case of CIFS repository, then this traffic goes back and forth between your backup server and CIFS share.

Making NAS an iSCSI target should also work, cause iSCSI target is more reliable than CIFS. You can search these forums for more info about CIFS and Windows/Linux based repositories.