If you are looking for bigger packets have you checked to see if a jumbo frame 
can make the trip in one piece?
I agree that iSCSI may be slower due to less of the Ethernet packet being 
available to carry data because of the iSCSI information.

Ethernet[Tcp[iscsi[data]]]
Ethernet[Tcp[datadatadat]]
(Forgive the crudeness of the model; it is not made to scale.)

Andy Huebner
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Christian Svensson
Sent: Wednesday, May 27, 2009 10:52 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] SV: Performance question

Hi Kelly,
Thanks for the idea, but that is not a option for the customer. :(
If you think about it, theoretical it should go faster with iSCSI then normal 
IP traffic because you have larger packages sending and less overheads sending 
back and forward for each package. But this is only because of the large file 
size. If it was multiple small files such HTML normal IP traffic is faster.

I will probably test both technology to see what speed I get.


Best Regards
Christian Svensson

Cell: +46-70-325 1577
E-mail: Christian.Svensson AT cristie DOT se
Skype: cristie.christian.svensson
________________________________________
Från: ADSM: Dist Stor Manager [ADSM-L AT VM.MARIST DOT EDU] för Kelly Lipp 
[lipp AT STORSERVER DOT COM]
Skickat: den 27 maj 2009 17:35
Till: ADSM-L AT VM.MARIST DOT EDU
Ämne: Re: Performance question

I would guess that it won't go any faster via iSCSI.  Perhaps it might be 
slower due to one more protocol conversion on each end.

You can move about one quarter TB/hour over a GigE. So that's 1200 hours to 
move all that data...  That's a long time!

How about deploying another TSM server local to that data and doing the backup 
there and removing the tapes for DR?

Kelly Lipp
CTO
STORServer, Inc.
485-B Elkton Drive
Colorado Springs, CO 80907
719-266-8777 x7105
www.storserver.com


-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Christian Svensson
Sent: Wednesday, May 27, 2009 5:26 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] Performance question

Hi all *SMers
I got a new challenge in a front of me.
Every quarter will I get a large package with 10 000 new files where the total 
size is 300 TB of Data (each file is average size 30GB large). This is static 
data that will not replace any other files or modified.
The problem is that I can not do any LAN-Free backup over SAN because of the 
data and TSM is on different locations (20 Miles between the sites). The link 
between the data and my TSM Server is black fiber but I only have 1 GBit 
limited speed on this link. Why I don't know...
I don't have any time limit how long time it takes to backup/restore this 
files, even if it takes 1 hour or 30 days. The customer don't care.

But as TSM Admin I want to do this backup/restore as fast as possible.

I was thinking of to do a LAN-Free backup but via iSCSI so I sending larger 
blocks between server and tape but I don't know if that will give me any 
performance benefit then backup as normal incremental backup over normal TCP/IP 
network.

My question is, will it go faster to do a backup via iSCSI then regular LAN 
Backup?

Best Regards
Christian Svensson

Cell: +46-70-325 1577
E-mail: Christian.Svensson AT cristie DOT se
Skype: cristie.christian.svensson


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