Files to Tape - incremental gettin slower and slower

[user_123]

Hi,

Very new Veeam User here and I am very satisfied with the product.

I want to Backup files from a local disk on my Veeam Server to tape. I created a new Files to Tape Job for that case. I need only the files which have changed since the last Job. On that Disk are Database Dumps. The first File to Tape Job ran and backed up alle files from that Disk. On the second day (i configured only incremental) the Job backed up only the Dumps wich are new and not on the tape, I thought - oh yea! - this is excactly what i need. I let it run over the weekend (everyday incremental). Today i noticed that the Performance of this Job is drastically slower than on the first and second incremental. Down from 150mb/s (500GB/h) to 24mb/s.

If I do an active Full Backup (write all Dumps on the same Tape) i am back to my old 150mb/s. Veeam could stupid write alle Files on the Tape at full speed.
Why is the incremental gettin so slow? Does the change block checking on the tape cost that performance? I am talking about very large files (100GB per File) not thousands of small files.

All i want is to backup only the latest Files to Tape (which are not on Tape). Are there any fixes or other ways for that?

[veremin]

The first question we have to ask is whether you're on the latest available product version or not?

[user_123]

Sorry for not sharing Informations with you regarding my environment!

Veeam Backup & Replication: 9.5.0.823
Windows Server 2012 R2 Standard
24GB Ram , 6 Cores E5-2430@2,5 GHz

Quantum i40, LTO6

Best Regards!

[Dima P.]

Hi user_123,

Can you clarify are using compression or encryption while writing files to tape?

I am talking about very large files (100GB per File) not thousands of small files.

Any raw estimate on number of files and overall size? Thanks.

[user_123]

Hi Dmitry!

It is a standard internal SATA (6GB/s) 3,5" Disk with 7200k rpm. On that Disk are ~15 100GB Database Dumps and ~4 10GB Dumps. Everyday there are 2 to 3 new 100GB Files and one new 10GB File.
I want to copy the 3 or 4 new Files on a Tape which aren't on a Tape in that Media Pool to have them else where stored. To remove the oldest File on the Disk i am using a "after Job" script in Veeam to do that. I Thought that a "File to Tape" Job with only Incrementals would fit perfectly my requirements. I Have now switched the Job to only Full every day to store them and i am Faster (150-160 mb/s) as only incremental (20-24 mb/s) regardless i have to copy all Files another time on the Tape rather than copy only the newest with incremental :\

The Database dumps are already compressed and the Tape Drive Hardware Compression is enabled. Software or Hardware encryption is disabled!

My assumption is that Veeam is trying to block deduplicate with every other incremental job on that Tape. The first and second Job ran with fullspeed cause there were no or very less Data on the Tape. With the third Job Veeam tries to only store blocks on the tape which arent in any other File on the Tape. Causing some very slow Random Block Reads resulting in the slow copy rate?