Ultrium 2 tape

[Stéphane Gauthier]

Hello all,

Ultrium 2 200/400 tape is supposed to hold up to 400Gbs compress. Using Data Protector 5.5, I can see that about 213Gbs is taken. I am just trying to understand how it does work. From my understanding, DP is starting to compress when it figures out that it needs to... is this correct? The chart pie is full 100%, but it is more than that cause from 200Gbs up, it is always saying 100%. I am not looking really for some questions/answer but maybe more for someone who does understand the whole process.

Tks.

[Steven Clementi]

Stéphane:

Data Protector reports the tape's capacity based on a value of 100GB. This is a soft setting within the software that can be changed, if you so choose... but has caused much confusion to date. The tape will hold the specified amounts and DP will continue to write to it even though the pie chart stats it is 100% full.


The process itself... DP backs up data based on your settings in the Backup Specification. I think compression is automatic and can be turned off.

In order to write the full 400GB or as much of it as possible, the compression needs to start at the beginning of the write process.


Steven

[Rob Leadbeater]

Remember as well that not all files can be compressed.

If your file system consists of files which are already compressed (zip files for example), then you won't fit 400GB onto a 200GB tape.

Regards,

Rob

[rich pattison]

Typically, compression is done on the tape drive itself - not by DataProtector (unless you tell it to use software compression in the backup spec). So DataProtector can't really "know" how much a cartridge will hold - it can be 200GB to 400GB or even more,
depending on the type of data you're backing up. Thats why its a "user" setting, rather than a calculation made by DataProtector itself.

Rich