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BRU LTO-5 and LTO-6 capacity

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Neil Sadwelkar
BRU LTO-5 and LTO-6 capacity
on Oct 9, 2014 at 1:26:48 pm

Just finished a long round of LTO-5 backups - 65 TB in all - spread over 51 tapes. Backed up with BRU-PE.

With each tape I did a 'How many tapes' to ensure it was all fitting in a tape each session before writing to tape.
I've found that the amount of data that BRU reports is about 4% more than the data that Finder shows (with a cmd+opt+I) on a group of folders. And, the maximum I can fit on a LTO-5 tape is just about 1,300 GB (by Finder, or about 1,350 by BRU)

With LTO-6, its about 2,200 GB per tape.

What's taking up the extra space? Just the decimal GB vs TB thing, or is it some directory info or some kind of redundancy info?

Just curious.

-----------------------------------
Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India


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Tim Jones
Re: BRU LTO-5 and LTO-6 capacity
on Oct 19, 2014 at 7:52:41 pm

This is related to the actual recovery metadata that BRU's archive container format includes in the archive. Depending on the data types and block size used, that can range from 8%-15%.

That added data is what allows BRU to recover data from archives that other applications and formats would simply give up on.

Tim
--
Tim Jones
CTO - TOLIS Group, Inc.
http://www.productionbackup.com
BRU ... because it's the RESTORE that matters!


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Neil Sadwelkar
Re: BRU LTO-5 and LTO-6 capacity
on Oct 31, 2014 at 1:10:16 pm

Tim,

Thanks. The data I'm backing up for this project is ArriRaw files. These are one file per frame, So, a Terabyte could hold over 140,000 files. Whereas when one is backing up Red Raw, or F65 Raw files, these are one file per 'clip'. So in 1 TB one would have about 200-400 files or so.

Does the number of files also affect this 8%-15% 'padding' (for lack of a better term)?

Also, speed. I find backing up ArriRaw (file seq) takes longer than Red Raw. Is this a 'nature of the beast' thing?

The total backup for this feature I'm doing has now crossed 120 TB (ArriRaw, Red, GoPro, Canon, Phantom, sound etc etc) spread over 93 tapes.
All Bru-PE
Whew!

-----------------------------------
Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India


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Tim Jones
Re: BRU LTO-5 and LTO-6 capacity
on Nov 15, 2014 at 7:23:23 pm

Hi Neil,

Sorry, this one slipped through the cracks - The Cow's forum layout can get things lost pretty quickly.

File size can affect the throughput because of more disk accesses. However, the average DPX or MXF frame file should be large enough to no affect the throughput (unlink 1 million mail files...).

What buffer size are you using in BRU PE? For media files, we recommend either 1MB or 2MB.

Tim
--
Tim Jones
CTO - TOLIS Group, Inc.
http://www.tolisgroup.com
BRU ... because it's the RESTORE that matters!


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