brbackup compression questions

[Former Member]

1) in SAP Note 163490 it mentions that hardware compression can be used

to compress backups to disk. Do i misunderstand and this if for tape compression ?

or if for disk how does it work ?

2) why is a compress_dir (and the space) needed if compression is done with

the unix compress program ? Is it not inline ?

3) if the compress_dir (and the space) is needed, and I write to multiple disks

backup_root_dir = (/backup/dir1, /backup/dir2) does the available space need

to be greater then the largest SINGLE file ?

[Former Member]

Hello Peter,

The note refers to compression done by some OS ( AIX, Windows ) at Filesystem level ( or drive in Windows )

It works the same as any backup to disk, with two differences

1) you must specify the parameter "compress = hardware", that way BRBACKUP will know it and use the compression rate to calculate the free space needed

2) you will have to run "compression runs" from time to time to calculate the compression rate ( same as tape compression )

The compression is not done by any compression program, this is not the same as using "compress = Yes" and "compress_cmd = "compress -c $ > $""

I do not see anywhere on the note the mention to "compress_dir", I think this is only needed if you use "compress = Yes"

[markus_doehr2]

[...]

> 2) why is a compress_dir (and the space) needed if

> compression is done with

> the unix compress program ? Is it not inline ?

Quote from the note: This function is also supported by BRARCHIVE. However, since it does not affect the BRARCHIVE logic there, this is not relevant - so it's not "inline".

[...]

The other two question I don't know - maybe someone else does

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Markus