Hi,


We have a strange performance issue with staging from Disk to Tape.

Config:
Sun V440 as Master/Media Server
Storagetek FlexLine640    used as Staging Device
Storagetek L700 w. LTO3

SIZE_DATA_BUFFERS          2048k     
NUMBER_DATA_BUFFERS        16
SIZE_DATA_BUFFERS_DISK      2048k     
NUMBER_DATA_BUFFERS_DISK    16


When we use the Flex640 as a "normal" Storage and doing Backups from 
Disk to the L700 Storage,
we see ~140MB/sec. throughput to one LTO3 (higher than expected).

When we use the same Volume on the Flex640 as an Disk Staging Unit an do 
manual relocate to 1 LTO3
we only see ~70MB/sec.

When we are using two staging units on the flex and are staging to 2 
LTO3 we see ~50MB/sec. per drive.
An overall of 100MB/sec.

Since Staging is done via bpduplicate, are there any settings that are 
staging, or bpduplicate specific?
It looks like that there is an "internal" limit, because tape, disk and 
system have spare resources left (enough idle time)


do you have an ideas?

thx
Jochen


-- 
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Jochen Pressler

Bacher Systems EDV GmbH
Clemens-Holzmeister-Strasse 4 ,  A-1100 Wien, Business Park Vienna,
phone: +43 (1) 60 126-34 | fax: +43 (1) 60 126-4
jo AT bacher DOT at | http://www.bacher.at

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