The LTO-1 data transfer rate (write speed) is 15MB native and 30MB
compressed.  Even though you can pull data over your Ethernet interface
in excess of 100MB/sec the bottleneck will either be your SCSI card or
your tape drives. You didn't mention the type of SCSI cards but if you
say it tops out at 40MB/sec then I would say you are using either a Wide
Ultra SCSI (16 bit bus)Card or a Ultra2 SCSI (8 bit bus)Card, both of
which have a MAX data burst rate of 40 MB/sec.

Dana 

-----Original Message-----
From: Legato NetWorker discussion [mailto:NETWORKER AT LISTMAIL.TEMPLE DOT EDU]
On Behalf Of Michael Hurst
Sent: Wednesday, May 05, 2004 12:09 PM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: [Networker] What speed can we expect on a Gb network?

Hi All,

We recently setup a Gb network between 4 Linux 6.1.3 clients and our
Solaris 6.1.3 NetWorker Server.
When we backup the clients to 3 LTO-1 drives we get a rate of 14MB/s on
each drive.
When we add a fourth drive to the backups, the rate drops to 10MB/sec on
each drive.

We then put a port monitor on the connection to the NetWorker Server.
No matter how I change the number of clients, target sessions or
parallelism we top out the connection at just over 40MB/sec.

We were wondering if this is the maximum transfer rate we will see on
the Gb interface or if we need to tune tcpip.
Is anyone seeing better speeds on the Gb NIC to their NetWorker Servers?

Note: NetWorker Server is a Sun Fire 280-R with dual 700Mhz CPUs and
1.5GB of RAM.
Still shows lots of CPU and memory available during the backups.

TIA,
Michael Hurst
University of Toronto
Email: michael.hurst AT utoronto DOT ca

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