Backup to Tape is very slow

I tested Novabackup 12.1 with a LTO5 Tape Drive which is connected to a LSI SAS HBA 3442e. I wrote about 100 GByte non compressable data to the Tape drive. Each file was > 2 GByte of file size. The hard disc was not fragmented.
I´m rather disapointed to see only a transferrate of less than 50 MByte/second. The Tape drive itself is able to process 140 Mbyte/second.
I checked the block size of the data on the tape and was suprised that Novabackup wrote the data with only 32 KByte to the tape. 32 KByte blocksize is ok for earlier generations of tape drives like DAT, VXA, SLR but not for the last generations of LTO. I guess that the transferrate is much better with higher blocksizes (128kB - 512 KByte).
Is there a chance to increase the blocksize, maybe with a Windows registry patch?

You said that the 100GB of data you were testing with was "uncompressable".

Just out of curiosity, did you un-check "compress backup files" on the Settings for the job?

Also, is this an HP brand tape drive? If so, did you first run the L&TT Tape Tools utility to disable hardware compression (if that is an option)?

I have both DDS5 (DAT72) and DDS6 (DAT160) SCSI DAT tape drives in my machines. When I do my backups of uncompressable data I first take both actions, suppressing compression in NovaBackup and also turning off hardware compression on the tape drives.

When writing uncompressable data, these actions not only produce better significantly better (e.g. 10%) use of the tape media, but also significantly better "speed" (i.e. MB/sec) and thus faster backup jobs.

I've compared backup speed using uncompressable data as above, for NovaBackup under Win7 and the previous Sonic Backup MyPC v6.0 that I was using under WinXP, with the same SCSI DAT tape drives. There is effectively no difference, and both products are coming close enough to the rated WRITE speed of the drives that I'm satisfied.

But I do agree with your own observations using your LTO5 drive (which is significantly faster even than my DAT160 drive) and I too would be looking for better performance.

I've not heard anything from NovaStor about the ability to increase blocksize, though I agree with you that this tweak does seem like the probable place to improve tape drive performance if at all possible.

Have you ever used this tape drive with another software product and gotten better performance than you're currently seeing with NovaBackup? With another computer? Have you tried the same backup using say HP's Data Protector Express (in trial mode, available from download), just to see a comparison??

Personally, I tried Data Protector Express and felt it was ridiculously priced, under-engineered, and produced no difference in performance... namely, again, close to tape drive rated speed. I went with NovaBackup because of its much friendlier user interface.

You didn't mention your Windows OS? Win7? WinXP? Something else?

One thing that is seriously defective (well I think so, anyway) about the NovaBackup architecture for tape backups, and that is that it does NOT use "hardware tape index marks" to separate files on tape. Nor is there a "contents directory" in header records on the tape, providing the contents of every folder/file on the tape and exactly where it is as a function of "hardware tape index marks".

This means that RESTORE from tape is handled as one long READ operation, actually passing tape at the same READ speed which was in effect when the WRITE of the tape occurred initially. So, if it takes 3 hours to essentially fill a tape with data when taking the backup, it will also take 3 hours to recover even one single file from down at the very end of the tape. And that's because the tape is passed using a READ technique, simply reading the data until the requested file is eventually located (based on some file prefix record probably, on the tape just in front of the file).

In contrast, my WinXP tape backup product (Sonic Backup MyPC v6.0) was designed for optimal use of tape. This included (a) tape volume label, written at new blank media initialization and never erased, thus providing "auto-recognition" of the tape media name when you use it for output, (b) tape directory table-of-contents header record, written after completing the backup and rewinding the tape, to allow for precise "spin-positioning" at RESTORE time, and (c) "hardware tape index marks" so that the tape could be SPUN (at hardware SPIN speed) some exact number of index marks, allowing for positioning to a file for RESTORE in remarkably little time.

For example, my DAT160 drive can spin-forward an entire 80GB (native) tape in 90 seconds. So RESTORE of one file from the end of that tape would take 90 seconds using Backup MyPC, and 3 1/2 hours using NovaBackup.

I mention this, just in case you are running that LTO5 drive on WinXP. I can say that I would still be using Backup MyPC if I was still running WinXP, if for no other reason than this radical advantage in RESTORE time provided by the "proper" tape index mark design used by Backup MyPC.

Thanks a lot for your detailed response.

>did you un-check "compress backup files" on the Settings for the job?
Yes.

>is this an HP brand tape drive?
Yes. I will try to disable hardware compression. But so far as I know does the drive automatically switch off hardware compression, if the data is not compressible.

>have you ever used this tape drive with another software product / computer ....
Not yet.

>you didn't mention your Windows OS?
Win7 x64

>...that it does NOT use "hardware tape index marks"...
Indeed, in general a big disadvantage but not so important for me. I need a software only for backup/restore and not for archiving. I hope that I never have to use the restore function. And if this really happens sometime, the cause for this most probably will be a defect hard disc. In this case I have to restore the complete disk anyway.

I will continue testing to improve the data throughput. If I have any news, I will post it here.

Thanks again.

>is this an HP brand tape drive?
Yes. I will try to disable hardware compression. But so far as I know does the drive automatically switch off hardware compression, if the data is not compressible.

I don't know how that's possible, since a backup job can write a mixture of anything... some of it highly compressible and some of it uncompressible..

The "hardware compression" feature is a hardware option, and you use the LT&T Tools program from HP to manipulate that option, although a software product (e.g. NovaBackup) could also do the same thing. In fact, NovaBackup does NOT touch the hardware compression setting of the drive at all, but rather leaves it exactly as whatever it's set at. Which is why you need to first use HP's utility to turn the option off, if that's the kind of backup job you're running where having NO hardware compression would improve media and drive performance.

I mention that in contrast, Sonic's Backup MyPC v6.0 (which I used under WinXP before upgrading to Win7 and being forced to find another product) actually DOES always turn "hardware compression" on before the job begins. This was frustrating, as I couldn't disable the feature before running a backup of uncompressible data as I wanted to. So in that regard, NovaBackup is "superior" to Backup MyPC, as it does not tamper with that feature and let's the user pre-set it to whatever the user wants.

>have you ever used this tape drive with another software product / computer ....
Not yet.

Well then there's really nothing to compare it too. Software products that do blocking, add overhead with header fields, etc., rarely if ever can achieve the hardware-rated speed that is theoretically possible per the manufacturer's specs.

Just for the sake of experimenting and gathering some comparison statistics to see how your LTO drive performs with other software, why don't you install trial versions of some other products and run some experiments? I'd be interested in seeing those numbers.

Personally, I've tried the following three other products (since they supported SCSI DAT tape drives, which was a requirement for my product selection) and didn't like any of them. I ultimately settled on NovaStor (although I do have a good-sized list of product improvement suggestions I've sent to them).

(1) Uranium Pro Backup ($213): http://www.uraniumbackup.com/index-en.aspx

(2) Acronis Backup and Recovery 11 Advanced Workstation ($99): http://www.acronis.com/backup-recovery/#overview

(3) HP Data Protector Express ($650): https://h20392.www2.hp.com/portal/swdep ... mber=DPXSW

>you didn't mention your Windows OS?
Win7 x64

Well then that leaves out Sonic Backup MyPC v6.0 as another option for you, if it even supported LTO tape drives.

>...that it does NOT use "hardware tape index marks"...
Indeed, in general a big disadvantage but not so important for me. I need a software only for backup/restore and not for archiving. I hope that I never have to use the restore function. And if this really happens sometime, the cause for this most probably will be a defect hard disc. In this case I have to restore the complete disk anyway.

Actually, for me it is completely the opposite.

I only use the "full restore" functionality if say I'm upgrading a hard drive to a much larger one. Otherwise, virtually all of the occasional restore usage I get is "selective restore". And because of the built-in serious performance defect of NovaBackup and tape (i.e. that it does NOT use hardware tape index marks for positioning) I have specifically begun using disk backups for 1-2 most recent generations, along with 4-6 generations on tape. Since almost always getting a prior version from the most recent 1-2 generations is what I want, there's no performance issue when using the disk backup media for the selective restore.

But if I was using tape, I'd sure hate to spend 3 1/2 hours getting one file back (using the READ method) when it should have taken 90 seconds (using the SPIN method).