backup utility

[vijay2102]

i have use the hp data protector Express for data backup purpose and use the ultratrim 3 lto media with 800 gb capcitiy device but last three time when i take the backup he shold be only take bakup 500 gb and pending data demand the another device so plz help to me

[Chris Ciapala]

LTO3 has 400GBs native capacity without compression. 800GB is marketing term, used with assumption of 2:1 compression. If you backup normal mixed content of files from typical file server or database, than most likely it will hit this level, however if you have some already compressed content, than amount of data written to tape will be lower.

[OldSchool]

plus, there may be existing / protected data already on the tape...if so, it won't be overwritten, only appended to.

the only time the tape will be reused from the beginning is if there isn't any protected data anywhere on it. Consider:

Backup 1 - expires 9/10/2008
backup 2 - written 9/9, expires 9/17/2008
backup 3 - written 9/16....

backup 3 will not have access to any of the space used by 1 or 2. 2 appended to 1, 1 expired but the space can't be reclaimed.