Networker

Re: [Networker] licensing requirements for driving library's drives with > 1 server

2005-12-12 19:57:47
Subject: Re: [Networker] licensing requirements for driving library's drives with > 1 server
From: Peter Viertel <Peter.Viertel AT MACQUARIE DOT COM>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Tue, 13 Dec 2005 11:51:14 +1100
LTO-3 drives can run at half speed, and I believe some other speed
breakpoints as well... So even if your network does turn out to be a
bottleneck there should not be a problem with shoe-shining your
drives... 


-----Original Message-----
From: Legato NetWorker discussion [mailto:NETWORKER AT listserv.temple DOT edu]
On Behalf Of Tim Mooney
Sent: Tuesday, 13 December 2005 8:42 AM
To: NETWORKER AT listserv.temple DOT edu
Subject: Re: [Networker] licensing requirements for driving library's
drives with > 1 server

In regard to: [Networker] licensing requirements for driving
library's...:

> It seems to me that in order to accomplish this I can
> (a) get a low-end Sun box capable of driving 6 LTO3 drives over fiber
(i.e.
> maybe a 440), or
> (b) continue to use the SF280s I'm using now, each driving two LTO3
drives.
>
> I'm uncertain what sort of licensing requirements there would be, were

> I to go with option (b).
>
> For a couple of reasons I won't get in to here, I do not plan to back 
> up data in a SAN (i.e. backup traffic will traverse our gigE switched 
> network
> instead.)

How many GigE interfaces are there on your server(s)?

With a theoretical maximum of ~ 125 MB/s and an actual maximum much
lower than that, you may not be able to push even one LTO3 drive over a
single gigE link.  I'm not sure if Solaris 10 is supported yet as a
backup server (we use Red Hat Linux), but graphs I've seen indicate that
the new TCP/IP stack in 10 does indeed improve performance
significantly.

If you only have one gigE link coming into the server, you'll need to
consider backup to disk, possibly followed by staging to tape.

BTW, I was at LISA '05 last week, and went to a number of the
backup-related BoFs.  Curtis Preston hosted a few of them, and he really
stressed the point that a single gigE link just won't do it for even the
previous generation of tape drives.

Tim
-- 
Tim Mooney                              mooney AT dogbert.cc.ndsu.NoDak DOT edu
Information Technology Services         (701) 231-1076 (Voice)
Room 242-J6, IACC Building              (701) 231-8541 (Fax)
North Dakota State University, Fargo, ND 58105-5164

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