Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

I am using BackupExec and it is asking for second tape. I am using LTO-3 ultrium 800 gig 2:1 compression tapes and it stops and asks for secound tape at 558,916,035,547 Byte count. Is my setup wrong or do i just need to get larger tapes?

share|improve this question

2 Answers 2

up vote 6 down vote accepted

LTO 3 has 800 GB capacity at the assumed compression ratio of 2:1, which is very optimistic in most cases. The physical capacity is 400GB, and in my experience a compression ration between 1.1:1 to 1.5:1 is much more realistic, but that is very much dependent on your data.

If you have an LTO4 drive, you could also use LTO4 tapes which have double the capacity. LTO-5 is the current generation with 1.5TB native capacity, but these drives can only read LTO3 tapes, not write them.

For more info, see Wikipedia.

share|improve this answer
    
thank you for the response that is what i thought ordered bigger tapes . :) –  volcer Feb 28 '12 at 17:20
    
+1. Actually you may have a backup software already compressing which then means the tape has little left to compress ;) –  TomTom Feb 28 '12 at 17:20
    
@volcer: Using LTO4 tapes is only working if you have an LTO4 drive, so be sure to check your drive type. –  SvW Feb 28 '12 at 17:22

What that means is that you get 800GB when the compression is 2:1. You must be getting less than 2:1 compression so that's why you're only getting 550GB or so on your tape. Nothing is wrong with your setup.

share|improve this answer
    
thank you so much for the response i thought that was the reason –  volcer Feb 28 '12 at 17:01

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.