[Raul Zeummes]

Thanks for your reply david.

Below is the result of the aja system test, it seems to match up with the atto one.

I was under the impression that the blackmagic decklink 4k extreme 12g did do hardware acceleration for 4k playback, on their site it says capture and playback in 4k.
If that’s not the case, what is a good hardware accelerated 4k playback card ?

Also, do you have any idea what could be going on with my varicam files ?

Thanks for your help,

sam

[Raul Zeummes]

Hi Tim,

Thanks for taking the time to address my points in detail.
My first BRU backup test ran overnight with no errors.

My main question at this point is as follows :

Do you recommend using BRU during a shoot as part of the offload workflow ? If so, how ?

I’m looking for a simple, GUI, time-effective way to copy footage off the cards onto a hard drive and a tape, and have both copies verified, before we format the card and give it back to the camera operator for re-use.

Thanks

[Raul Zeummes]

I’m writing for anyone who is going through this decision process now or in the future, because I haven’t found as much information as I would have liked about it.

My situation is as follows : I’m looking to use an hp ultrium 6250 drive to make quality backups of video footage during filming, and also to make long-term backups of general company files in a manner that is not particularly time-sensitive.

My preference was for a pc-based workflow, and a very affordable solution. (this eliminates all the $6000+ solutions)
I first tried the xendata ltfs software, and the people over there were extremely nice, available, and helpful.
A first issue where the software would just crash explorer without giving an error was tracked down to the length of filenames. Once I fixed all the file names, I still had random crashes of explorer (ie would crash on a given data set the first time, but not on the same data set on a second try)
In any case, there is no possibility of tape spanning, so you need to manually select combinations of files and folders that are 2.07 TB, which is not fun.

I started looking at mac based solutions, and quickly narrowed things down to PreRoll Post (prp) and Bru PE.

PRP post is LTFS based, whereas Bru has their own proprietary system.

Above we have a conversation between Dan Montgomery, president of Imagine products, the makers of PRP, and Tim Jones, the president of the Tolis group, makers of Bru.

In my reading of it, Tim seems to have a much deeper mastery of all the detailed technical aspects, and you can tell he has learned a lot from being in this field for so long. He has answers for all of Dan’s points. Some of Dan’s statements seem to have been intended to gloss over or mislead on certain points.

Here are some advantages I see to using BRU :

It seems to have the highest reliability. Lots of people who need high reliability use it.
It’s been around for quite a while.
Their president really knows his stuff.
A windows version is announced
Does tape spanning (so does PRP)

Disadvantages to using BRU :

I’d be keeping my files in a proprietary format. There’s only this one company that’s responsible for it, and who knows where they’ll be in 30 years.
You can’t backup to a tape and a disk in one operation. (which you can in PRP) If they did add this functionality I would assume the files would be in bru format on the disk, which seems undesirable.
The interface is much less straightforward, even confusing at times. Why does it say LTO5 everywhere when I’m using LTO6 ?
Many comments on the web about BRU being frustrating to use.

Here are some advantages I see to using PRP :

The interface is really excellent
You can very easily make a backup to a disk and to a tape in one operation as your media cards are coming out of the camera.
Does tape spanning (so does BRU)

Disadvantages to using PRP :
The company making it is younger
The ltfs format seems to be inherently less safe than the bru format, which is an essential point for backups.
Their president’s points online seem to lack clarity, and possibly forthrightness

The question for me comes down to how unreliable is ltfs really going to turn out to be ?
The bru folks have a lot to say about that, but not all of it is pertinent to PRP.

– “open source means no support” : PRP is supported by imagine
– “corrupts the backup if the system hibernates” : I’ll turn off hibernation
– “do not use ltfs as a live filesystem” : I’m not intending to, that would be silly
– “use finder/explorer replacements sparingly” : don’t need to, I’ll be going through the backup database
– “multiple simultaneous access not recommended” : don’t need it
– “do not access the tape between writes if writing multiple segments” : don’t intend to
– “additional write access will run more slowly than first write” : this is no problem for big data sets, but seems like it would be a drag during a shoot. I wonder how much more slowly, considering I’m not intending to unmount / remount.
– “updating files does not release space” : I won’t be updating
– “do not use to playback music or video” : we get it, it’s not meant to be used as a live filesystem
– “ltfs doesn’t offer a verification mechanism” : but as far as I can tell, PRP has saved an MD5 of every single file. it compared the original hashes to what was written after the backup.
– “ltfs tapes can only be used with ltfs” : I’m going to be going all bru or all ltfs anyway

Outstanding questions in my mind :
– why is bru adding ltfs functionality if the format itself is so bad ? the fact that they are doing that gives me the impression that ltfs is here to stay, and that it can’t be all that insecure if properly implemented.
– If the power cuts out during a backup (which I’m going to be doing all I can to avoid), I’m going to assume I’ve lost the data on the tape, and start the backup from scratch anyway.
– is there a way to lose data during a read-only operation on ltfs due to a power loss ? (this would be much more worrysome)
– when I came back to PRP after an overnight backup test (small, under 300gb), I had a mac system message that the software had crashed. But I also still had a window showing the details of the backup having been completed, and all the md5s having been completely verified. how often is it going to be crashing ?
– from what I can tell so far, in PRP you can search your backup database for a file, and get the result, but if the tape containing that file is offline, you can’t get the file’s path. (using the print function) because you can’t put an offline file into the retrieval section
– how will PRP do on a backup test spanning multiple tapes ?
– how will BRU do on the backup tests which I’ve started today ?
– I still have to look into PRP to see if there’s a way to compare a live file to a backup reference file in order to check if the live file has been corrupted for example
– apart from the power being cut during a backup, what are the other risks of using the PRP implementation of ltfs ?

If anybody has anything to add to the comparison process I’ve outlined above, I would be most grateful.
If not, I hope it can help somebody going through this process at some point