Plain arithmatic:

6 x 40 MByte = 180 Mbyte/sec x 8 = 1440 Mbit/sec

Isn't this a bit much for a single!!! Gigabit link ??

Not having much recent experience with Gigabit performance I would use a
conservative estimate of maximum 50 Mbyte/sec on a single GBE. This means
that it should be possible to drive 2..3  x LTO 2 drives at 130% which
equals to about 39..59MByte/sec, IF the client is able to deliver that load
!!

Before replying that you have dual GBE, I suggest you study the
documentation AND your configuration. I am 100% sure that you will find that
it does not work! The reason for this is that you do not have anything that
can be used to share the load because a session (backup stream) can only use
one GBE, and you do not have anything that can be used by a load sharing
algorithm unless some fancy drivers have been installed (does Sun have any
?) that allow two bytes to be transfered over parallel links. (never heard
of such thing).

The problem is that with trunking an algorithm is used to distribute the
load over the GBE's. This algorithm can be based on IP-address (you only
have one) or on MAC. However the MAC is normally used by a switch to
distribute and not by the network driver.

I can be wrong (I am open for corrections) but a trunked dual GBE between
two systems is useless. You should have more success if you use them as
single interfaces each with it's own IP-address so that you can distribute
the load using the hostname (but that can cause all kinds of side-effects in
Networker behaviour).

My advise, if you really need performance then upgrade the client to become
a storage node with direct attached drives or upgrade to 2GBit Ethernet (or
10GB when it becomes available) but then you may run into another
bottleneck.

Bye
Ernie


----- Original Message -----
From: "Alex Theodore" <alex AT FUZZYCHEESE DOT COM>
To: <NETWORKER AT LISTMAIL.TEMPLE DOT EDU>
Sent: Sunday, January 11, 2004 5:19 PM
Subject: [Networker] Performace isssues with LTO 2 Ultrium and unable to
write to all tapes at same time


> I am only getting about 3-6 megabytes/s when backing up to LTO 2 tape
drives.  I would expect that I should get somewhere near the advertised
value, but I am not.  Here are the details.
>
> - Legato Network 6.7.1
> - Solaris 8 (latest patches)
> - Sun L700 with 6 HP LTO 2 tape drives
> - Backup Server is a Sun Fire V880
> - Backup Client is Sun Enterprise 4500
> - Network pipe for backups is a dedicated, directly connected (no switch),
dual gigabit ethernet, which is trunked (glued together into 1 virtual pipe)
>
>
> The data on the client which is being backed up are images (photos) which
are a few megabytes in size.  I decided to split up the save sets into 6
different client configurations with the parallelism set to 6 so that all 6
tape drives would be used at the
>  same time during backups but this isn't happening either.. I can only
seem to write to a few tape drives at once..
>
> Any ideas would be greatly appreciated.
>
> TIA,
>
>   Alex
>
> --
> Alex Theodore
> alex AT fuzzycheese DOT com
> Boca Raton, FL  USA
>
> --
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