Networker

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

2005-12-13 11:43:54
Subject: Re: [Networker] licensing requirements for driving library's drives with > 1 server
From: Matthew Huff <mhuff AT OX DOT COM>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Tue, 13 Dec 2005 11:42:41 -0500
Well, first those numbers are "theoretical", not real world. Also, we
have one gigabit interface running jumbo frames connected to a backbone
with two NetApp 960 servers and another 2nd gigabit interface running
normal framing connected to the rest of the world. The original context
that this thread was on was the fact that Sun Solaris would have
difficulties running full speed gigabit, but my point was with tuning it
can.

----
Matthew Huff       | One Manhattanville Rd
Dir of Operations  | Purchase, NY 10577
OTA LLC            | Phone: 914-460-4039
www.otaotr.com     | Fax: 914-460-4139   



 

> -----Original Message-----
> From: Legato NetWorker discussion 
> [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On Behalf Of Tim Mooney
> Sent: Tuesday, December 13, 2005 11:22 AM
> To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
> Subject: Re: [Networker] licensing requirements for driving 
> library's drives with > 1 server
> 
> In regard to: Re: [Networker] licensing requirements for 
> driving library's...:
> 
> > Actually, that isn't quite accurate. Even under Solaris 9, 
> if you tune 
> > the gigabit ethernet card and TCP/IP as well as use a separate VLAN 
> > with jumbo frame support, you can drive signficantly higher 
> > throughput. We use a Sun V490 and and keep 6 x LTO-2 drives 
> spinning at max.
> 
> I'm not sure I understand.  Are we on the same page, that a 
> gigabit ethernet interface means an interface with a maximum 
> transfer rate of
> 1 Gigabit per second, and that converting that to bytes means 
> a maximum transfer rate of approximately 125 Megabytes/s?
> 
> If we agree on that much, then we agree that the absolute 
> maximum amount of data anyone can push through a single 
> Gigabit ethernet interface, per second, is approximately 125 
> MB.  That's assuming no overhead whatsoever.
> 
> Searching on the net, I see that the maximum transfer speed 
> of an LTO-2 drive in *uncompressed* mode is 30 Megabytes/s.  
> That's *without* compression.  Is that figure incorrect?
> 
> Assuming that figure is correct, your assertion of pushing 6 
> drives at maximum throughput (assuming uncompressed mode) amounts to
> 
>       6 drives * 30 Megabytes/s = 180 MB/s
> 
> One of us is clearly incorrect -- if it's me, I would be 
> thankful if someone would point out where my misunderstanding is.
> 
> Tim
> 
> 
> > --
> > Matthew Huff           | One Manhattanville Rd
> > Director of Operations | Purchase, NY 10577
> > OTA LLC                | Phone: 914-460-4039
> > mailto:mhuff AT ox DOT com    | Fax:   914-460-4139
> > -----Original Message-----
> > From: Legato NetWorker discussion 
> > [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU]
> > On Behalf Of Tim Mooney
> > Sent: Monday, December 12, 2005 4:42 PM
> > 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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