[rhn-users] Backup problem using DLT Tape Drive in LINUX

[cbeerse at gmail.com]

Ramesh R wrote:
> Hi,
>    Iam from India and we have installed Linux ES Verion 3 on DELL SERVER
> POWEREDGE 2850 series which has following configuration: Dual Processor
> with 4 GB RAM ad 4 * 72 GB SCSI Hard disk Drives With RAID 10
> technology. We have implemented Oracle Applications ERP . We have a
> peculiar problem for backing up  our data. We have connected DLT Tape
> Drive VS80 40/80GB ( Tandberg)  capacity with SCSI Adaptec Card. When we
> initiate backup command as follows:
>     dump of /dev/st0 /data/erpp where /dev/st0 denotes the device for
> tape drive and /data/erpp is the partition in which oracle apps has been
> installed. The timing for backing up 63GB data and files , it takes 18
> hours for completion. We had replaced the SCSI adaptec card , Tape Drive
> and cable but still it gives same timing. 
> The same process we had tried from a desktop by applying latest SCSI
> drivers  and initiated the backup , it took 12 minutes for 2 GB of data.
> We had applied latest driver for Linux but still it shows the same
> timing. I need to know any other parameters needs to be configured under
> Linux. I need help more urgently as we are going online by next week.
> 

While dumping, listen to the tape. It should be in streaming mode: the data 
should feed as fast (faster than) the tape can hanlde so the tape does not need 
to wait for data. Listen to the drive while doing the backup, I bet it is 
spinning forward and backward all the time.

Get a better backup tool that can dump data to tape with the tape in streaming mode.

You can also twiggle with the compression. Disable the hardware compression and 
see if the tape now gets streaming. If you need compression (for the size) try 
software compressing (`compress`, `gzip`, `bzip2` or such).


Success

CBee