On 1/18/2007 1:38 PM, Ellis, Jason wrote:
> I?m testing FlashBackup to backup a large volume with millions of small 
> files at raw volume speeds with the ability to perform single file 
> restores. I know FlashBackup supports multiple data streams with 
> multiple devices, but is there a way to use the NEW_STREAM directive on 
> a single volume to get multiple data streams from one device (this is a 
> large LUN with multiple spindles so I?m not worried about head 
> thrashing). I?m getting about 18 MB/sec right now (a far cry from the 1 
> MB/sec without FlashBackup) and would like to get more speed if 
> possible, hence multiple data streams. I?m thinking that it is not 
> possible since I am technically accessing raw volume, not the file system.

You are correct - this is not possible.  In order to get multiple data 
streams working, you'd have to walk the file system.  The reason 
FlashBackup goes as fast as it does because it does not walk the file 
system.

You wouldn't get better performance by using more streams - you'll do 
much better by optimizing the disk reads and the network transfers. 
I've seen FlashBackup jobs top 60 MB/sec here.

        .../Ed


-- 
Ed Wilts, Mounds View, MN, USA
mailto:ewilts at ewilts.org