Hi,
We are using Backup Excec 15 and HP tap library with LTO6 Tap. Even I enabled compression with backup, the media capacity is showing as native capacity (2.38TB) instead of Compressed capacity. So I fear I'm losing remaining all space of 6TB tap. Hope some expert advice to solve this issue.
aimsholding wrote:
Hi,
We are using Backup Excec 15 and HP tap library with LTO6 Tap. Even I enabled compression with backup, the media capacity is showing as native capacity (2.38TB) instead of Compressed capacity. So I fear I'm losing remaining all space of 6TB tap. Hope some expert advice to solve this issue.
Backup Exec only reports the native capacity in the "media capacity" field, as that is all that can be assumed can be written to a tape. 2.38 TB is the normal native capacity for an LTO6 cartridge.
When the "backup data written" exceeds the "used capacity" (as it does in your screen shot), then you are getting data compression (as your screen shot indicates 1.13:1 compression).
Obtaining the 6 TB that is advertised by the marketing teams of the tape companies are theoretical and it all depends upon YOUR data. Some data is more compressible than other data. The marketing folks are speculating that you can get data to compress at 2:1 or 2.5:1, which is realistic for some users and not for all.
If you want to get more data on that tape, you would need data that compresses better.
Refer HP document . You can check if a test can be done from HP tools with the same source data that you are backing up if possible to check on compression stats.
The compression depends on data being backed up.
Also, Go to Backup Sets section in Tape -> sum up all sets backed up to it and divide by space consumed on tape and confirm the compression ratio reporting is correct.
