357GB on SDLT tape 160/320 ??

[Padzik]

Hi,
My weekend job wrote 357 GB of file backup on the SDLT tape 160/320 (average throughput was 733 MB/min on the library MSL 5026). Could be any problems with restoring these files? I think, there is written too much on the tape :-(

 

[ARCguru]

Its called COMPRESSION!

I've seen 1 TERABYTE LOG FILES Happily be backed up and Restored from an LTO Drive.

I wouldn't have thought it is anything to worry about the tape drive manufacturers compression codes are good, I would hope it is compressed at hardware level not at software level otherwise the only impact you might see when you are restoring data is high CPU usage.

 

[Padzik]

Thanks a lot. It was backed up by HW compression.

 

[davidmichel]

As ARCguru said it is all up to the type of files being backed up. So if as in the case he pointed out you have some large text files they will have a high compression ratio and usually will exceed the marketing limit on the tape.

After all the top figure is set by marketing, and the bottom figure is real. That is the native capacity, in other words without compression. Beyond that it mostly depends on the type of data being backed up.

 

[Padzik]

Thanks !

 

[caroot]

Hi. When you see 357 GB in tape. it is all Mb backup in tape since first day that you use this tape 3 month age for example.

But if you are going to database, to media records you can see Mb in last backup and MB totally since first day.

Javi

 

[Padzik]

to caroot:
Of course, this was only ONE big full backup. The tape was erased before.