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Cross Checking info from Reseller

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John Weeks
Cross Checking info from Reseller
on Nov 5, 2010 at 1:56:31 pm

Hi folks

I've read several of the excellent guides from Bob and others on setting up a DIY SAN (based around a Mac Pro with a 4 port Small Tree card and a managed Switch) and finally sold the directors on the idea of implementing one for our 5 suite production company. However, one of them presented it to our IT support company who have thrown a spanner in the works on a couple of points and I would be very grateful for the opinion of people much smarter than I:

1. His first was on whether Apple's implementation of the LACP protocol was good enough to work for this purpose:
Apple’s system isnt even link aggregation/load balancing. It is actually a bonded link. This means that in Apple’s implementation, all data will be sent through the last NIC added to the set and little if any will bleed over to any other NIC’s in the set. So, in essence, its failover only and therefore not suitable for what you’d like to do.
Is he correct? And if he is, is this a concern or is the LACP part done on the hard ware side through the switch and card thus cutting out this possible problem.

2. Instead of trunking a connection from server to switch, could you make a direct link from a suite to a port on the server, thereby guaranteeing that a suite would have a dedicated pipe to the server? Would there be any benefit / detriment doing it this way instead of using a switch (aside from the expense of more network cards)?

Any thoughts people have on this would be greatly appreciated. For reference the hardware I was speccing out was:

Quad Core Xeon Mac Pro

Small Tree PEG4 Network Card

Netgear GS716T Smart Switch

Sonnet Tech Fusion RX1600RAID 32TB

Thanks a lot

John


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Jeremy Strootman
Re: Cross Checking info from Reseller
on Nov 5, 2010 at 4:54:06 pm

John,

I think the more concerning issue with the solution you are proposing is the cost of all of the components and the level of fault tolerance you are getting for that money.

It looks like you have budget for a real SAN solution from a single source vendor that would be easier to support from an IT standpoint, as opposed to the DYI solution you are presenting.

Ethernet will work wonderfully with the iSCSI protocol. I (along with some of my peers) have solutions that take Ethernet out of the workstations directly to Ethernet based storage. There is no need to convert topologies on the way down the pipe via a Mac Pro.

You might want to get some quotes for real SAN solutions.


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Bob Zelin
Re: Cross Checking info from Reseller
on Nov 5, 2010 at 5:20:28 pm

your IT vendor is incorrect. If you go to
http://www.bobzelin.com, you will see all the companies I have setup using this exact system.
Your Netgear switch is not the right product. If you contact me directly, thru my website,
to get further information on how to do this.

Resellers want their commissions, they see no financial value in what I have discussed.

Bob Zelin



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Neil Sadwelkar
Re: Cross Checking info from Reseller
on Nov 9, 2010 at 10:34:53 am

Bob, you've included a comma in the link to your page in your post, so the link doesn't work.

The link is
http://www.bobzelin.com

-----------------------------------
Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India


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Eric Hansen
Re: Cross Checking info from Reseller
on Nov 6, 2010 at 8:16:48 pm

hey John

i may be totally wrong, but this is how it's been explained to me. if you take 2 links and bond them together and connect 2 computers directly (no switch in between), it will work as you describe. you don't get twice as much speed. you don't get 2 connections. you'll only get one connection and the other one is there for redundancy. i don't know of anyone that's doing this.

our Ethernet RAID systems rely on a switch that can handle this link aggregated bond, which then doles out the individual connections to the computers. so 4 ethernet lines from the server to the switch will result in 4 independent links coming out of the switch.

yes, you can just connect a computer directly to the multiport ethernet card and you will get a direct connection. i do this with mobile editing servers (6 port card feeding 6 editing stations with no switch). the downside is that the shops that i build these SANs for typically have more computers than they do ports on the server. so having the switch helps to make sure the computers that currently need the bandwidth are getting it.

e

Eric Hansen - http://www.erichansen.tv


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Steve Modica
Re: Cross Checking info from Reseller
on Dec 30, 2010 at 4:47:42 pm

Sorry to be late to the party on this.
Some comments:
Link aggregation is good for many to one sharing scenarios (eg 6 ports, 20 clients). If you have 4 ports and 5 clients, just buy a 6 port card and give them each their own port (do not use the apple built ins because they have a nasty habit of queue stalling right now. I'd even put our cards in the clients.) The secret is that we use older chips and the errata list is very well understood. They are line rate and extremely robust.

The switch can be skipped and you can go direct. If you wanted to use a switch, Netgear is not the right choice. Edge-core is the least expensive thing you'll find that will do flow control correctly for this application. That's why we sell it. We offer the very lowest cost thing we can find that does it right. (And we've been through many firmware iterations with them BTW). Most vendors default flow control off and so they don't see many bugs on that feature. Thus it's often broken.

The Sonnet chassis looks like a Small Tree chassis. That's because the same company bends the metal. That's where the similarity is going to end. Almost no drives on the market will deal with a shared realtime load. Your chassis will have the wrong drives.
Most of these products are setup for drag races (one very fast stream). Shared storage is very different.

Steve

Steve Modica
CTO, Small Tree Communications


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