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sg_sc
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backup <1TB does not fit on 1 LTO-5 tape

Post by sg_sc » Feb 08, 2019 10:39 pm

Hello,

It's not really an issue, but I was hoping to fit this backup on 1 tape.

When trying to put a backup (latest full only) on a LTO-5 tape it doesn't fit and asks for a 2nd tape.
LTO-5 has a native capacity of 1,5TB (and 3TB compressed that you'll never get).
Why is it that a backup that's smaller than 1TB on disk don't fit on 1 tape then?

The original backup is made using Veeam Agent for Windows.
I have a backup copy job with GFS and only the minimum possible restore points for this 1 Agent Backup.

In my tape job I use the BackupCopy job as source, and I have it set to only use the latest full backup and not include incrementals.
On my first attempt Tape hardware compression was off (as is by default) on my second attempt it was on but still doesn't fit (almost ...).

This is a screenshot of the JOB statistics detail:
https://i.imgur.com/GlMEBxe.png

This is a screenshot of the properties in the backup files overview:
https://i.imgur.com/TLb4gbE.png

This is a screenshot of the backup files from the backupCopy Job that's used as source
https://i.imgur.com/9Ct79PK.png

Thanks for any insights.

csydas
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Re: backup <1TB does not fit on 1 LTO-5 tape

Post by csydas » Feb 09, 2019 6:04 pm 1 person likes this post

Probably you've got a bum write header on the drive.

Try a full tape write test with your vendor tools and disable compression and see how much it writes. I'll betcha it stops well before the 1.5 TB capacity.

Dima P.
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Re: backup <1TB does not fit on 1 LTO-5 tape

Post by Dima P. » Feb 12, 2019 6:38 pm

Harvey is right. Tape degradation can shrink the capacity of your media as tape drive might write identical data block several times if it's not readable during read check.

sg_sc
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Re: backup <1TB does not fit on 1 LTO-5 tape

Post by sg_sc » Feb 12, 2019 10:21 pm

Does this mean that even if the drive heads are failing, Veeam checked that every block written is readable?

elcotrade
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[MERGED] Tape Backup needs to much space

Post by elcotrade » Feb 13, 2019 9:50 am

Hi Guys,

i am using a Tape Job to backup my "Backup to NAS" Job to tape.
The last full file ist about 2,7TB big (compressed) and I am Using a internal SAS IBM ULTRIUM-HH6 Tape Drive with 2,3TB space (for compressed data).
The Job works fine since 3 years now. But now the Job needs 3! instead of 2 tapes.

After contact with Veeam Support, they analysed the log Files and told us that everything seems fine with the jobs and we should test the tape drive with vendor tools.
With the IBM Vendor tools "Write/Read" tests went fine, only at the Health test a "Performance failed" warning appears. But i don't know what this mean.

Does anyone has experience with such problems?

Thanks!

Windows Server 2008 R2
Newest Veeam Version
IBM Ultrium HH6 Tape drive (3.5 years old)
LTO 6 Tapes (about 85 write cycles)

Adrian1980
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[MERGED] Tape Backup needs to much space

Post by Adrian1980 » Feb 13, 2019 11:36 am

Hello elcotrade,

we had similiar effect on customer with a Dell drive, which is in fact a rebranded IBM.
Analysis by Dell resulted in broken tape drive, they replaced it and space consume went back to normal.

Greets,
Adrian

elcotrade
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[MERGED] Tape Backup needs to much space

Post by elcotrade » Feb 14, 2019 7:24 am

I have ereased the tape now with ibm tools, started a Veeam Job -> after 1,2 TB the tape is full.
I will order a new tape drive. I hope thats the issue..
Thanks

Dima P.
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Re: backup <1TB does not fit on 1 LTO-5 tape

Post by Dima P. » Feb 15, 2019 8:02 pm

Does this mean that even if the drive heads are failing
Tape getting old likely to be the root case. For drive issues, I'd recommend checking with the tape vendor's support (and perform drive cleaning prior calling support)
Veeam checked that every block written is readable?
Read check is performed by device itself. After block has been written to tape, device reads it. If read was successful - drive will write another data block, if read fails - drive writes the same block again and reads it again.

sg_sc
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Re: backup <1TB does not fit on 1 LTO-5 tape

Post by sg_sc » Feb 15, 2019 8:39 pm

My vendor tools also complained about health issues with the tape drive, so that's indeed the reason.

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Re: backup <1TB does not fit on 1 LTO-5 tape

Post by Adrian1980 » Feb 27, 2019 12:01 pm

Hello elcotrade,

is your problem resolved with the new Drive?
Would be nice to Add a [Resolved] to topic.

Greets,
Adrian

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