Shell Programming and Scripting

Hi,

I am restoring the database backup using compress utility(/usr/bin/compress) which takes around 1 hour.For restoration i use uncompress utility(/usr/bin/uncompress) which is taking nearly 6-7 hours.Can someone let me know how to reduce this time.I have pasted below the line from script which is used for uncompressing data :

Code:

for File in ${acFileList}
do 
 Uncompress=/usr/bin/uncompress
 ($Uncompress -cf $File 2>/dev/null > $acRestoreDir/${File%.Z} ; echo $?
$File >> $errorfile ) &
done

Regards
Santhosh Kumar N

Have you identifie the botleneck already? Is the CPU used for 100%? Where is the backup stored? On a separate disk?

I believe that the script is flawed. It is doing the equivalent of "zcat" and piping the output to a shell write. Without testing it I'm not convinced that the resultant file would be correct unless it was a text file. Also it will be very slow.
You need to do each uncompress in a directory which has enough space for the total size of the compressed file and the uncompressed file for the duration of that uncompress - even if it means copying each file.
Depends on local conditions.

Code:

uncompress ${File}.Z

i.e. Don't use the "-cf" switches.

When uncompressing multiple equal size database segments in a partition which is just big enough I temporarily move the first segment out of the way while uncompressing the last segment. This minimises data movement.