LTO4 1.6TB

[Weald_99]

Hi There 

I'm currently having problems with LTO4 1760 tape drive and Backup Exec 2010r2 ( Fully patched).

We are currently using 1.6TB tapes and Backup Exec want another tape at about 500GB. We have tried HP drivers just incase.

Has any had the same problems or got any ideas on setting. 

if you need any info on setup or setting please ask.

Regards

Dave

[Kiran_Bandi]

We are currently using 1.6TB tapes and Backup Exec want another tape at about 500GB.

Couldn't really understand. If you are expecting BE to use full 1.6 TB it may not use 1.6 TB all the time.

LTO4 tape capacity in Normal Mode 800GB. In compressed Mode 1.6 TB.

How much data will be written to a single LTO4 tape depends on the type of data. 

Regards...

[Ken_Putnam]

@Kiran and Joao

What you both say about compressed capacity  vs native is correct, but that should still get 800GB per tape, and the OP is only getting about 500GB

@weald99

Are you sure that you have LTO-4 media, not LTO-3?  500 GB would be about right for LTO-3 (I use 1.2-1.3:1 as a rule of thumb when estimating capacity)

Also, we have seen reports of BackupExec getting less than the native (uncompressed) capacity on LTO drive back as far as v11 and LTO-2  There has been no official solution, but a work-around that has been suggested is to use the drive manufacturer's utility to initialize the tapes rather than labeling it in BackupExec

[Kiran_Bandi]

another tape at about 500GB.. 

oops.. I understood it wrongly.

@Weald Sorry Mate..

[JoaoMatos]

Hi,

you should use Symantec tape drives.

Like Kiran Bandi says, data compressed depends the type of data you are backuping.

if a file does not support compression, the backup of that file is not compressed

EDIT: After Ken's post.

One day I´ll learn to read. Sorry

[pkh]

You situation is possible if you are compressing files which cannot be compressed, e.g. zipped or image files.  These kind of files can result in a bigger compressed file than the original file.  For an explanation, read my article below.

https://www-secure.symantec.com/connect/articles/compression-short-explanation

[Weald_99]

Sorry for the very very very late reply, I have been away on holiday and then sick leave.

For some reason it start working correctly for a bit then the problem start again. Same tapes have been used throughout. I have made sure that system has been fully up-to-date. 

@ Ken Putnam

How do you do you get it to initialize the tapes with the manufacturer’s utility?

I have just set the compression to hardware only to see how that goes. 

[Ken_Putnam]

Go to the drive manufacturer's web site.  In the Downloads, or Suport, or Utilities area you should find a program to manage the drive

For example, HP has LTT (Library and Tape Tools)

[Weald_99]

I have just spoken to one of the guys at HP ( we have a HP storageworks external SCSI 1760) 

He ran the L&TT software on the machine and checked the drive configuration through the health option and "data compression" was set to disabled. ( attached).

He then went to Utility > utility group > drive confirguation > options> enable Data compression.

Will update you the result.

Regards

Dave

[Mayuresh_Thule]

The compression is a ratio, so it always ends with ":1", so you can basically ignore that. The first number (the number before the : colon) is the key number. If is "1" (i.e. "1:1") then you are effectively getting no compression. If is "1.5" (i.e. "1.5:1") then you are getting medium (50%) compression. If it is "2" (i.e. "2:1") then you are getting good compression (100%). Any compressed data will only be backuped up its original size, then according to the configuration in the backup exec it can be compressed. Backup exec Compression depends on the Data type and the compression ratio cannot be identified for any data before it is backuped up atlest once.

[Ken_Putnam]

Mayuresh

All that is true, but does not address why he is getting less than the native/uncompressed amount of data on these tapes

[Weald_99]

right after the last update that I gave you it is still the same. 

in the mean time we have tried all the compression option with in Backup exec just to be sure. 

personally im starting to run out of ideas.

[mamilo]

Hi everyone,

I have the same problem like Weald_99. We have also LTO4-Tapes (800GB/1,6GB), HP 1x8 G2 Autoloader, SBE 2010 R3, latest patches installed

In the past we also had some compression :) , but now I also get only about 500-570GB on a tape (and the Used capacity shows that the tape is full). This happens with used tapes and with new tapes

F.E. Data: 567,8 GB,

Used capacity: 779,8 GB of 781,5 GB,

Available capacity 1,7GB,

Total cap.: 781,5

Compression ratio: 1:1

Please let me know if this issue was ever solved.

Regards

Milo

[CraigV]

Hi,

I have mainly MSL2024 G3 libraries (replaced the horrible 1/8 G2 autoloaders) and get the same compression I was getting in BE 2010 R1 as I am currently getting in 2010 R3...this isn't so much a case of a general issue, otherwise the forums would have been flooded with it. It's more along the lines of a per-installation issue...so it doesn't affect everybody.

Many reasons why you won't get 2:1 compression or sometimes even less, so read the TN below:

http://www.symantec.com/business/support/index?page=content&id=TECH6076

If you're getting less than 1:1, check the type of data you're backing up...already compressed data can, in some instances, inflate itself to a larger size during the backup.

Thanks!