Chris,

Again, thanks for the info.

I only have one server with a PERC (raid) card installed, and I beleive it is an older PERC 3 DCI, and doubt it would do the job. I would not be able to add more PERC cards to the other machines.

I am looking to have the connections all done via Ethernet. Again, the connections would be local (device to my switch, switch to the individual servers).

Does this mean I should be considering iSCSI, or, since the connections will all be on a local network, that I can continue to consider NFS?

Any takers?

-Grant

----- Original Message ----- From: "Christopher J. Umina" <chris.um...@studsvikscandpower.com>
To: "Grant Peel" <gp...@thenetnow.com>
Cc: <questi...@freebsd.org>
Sent: Tuesday, July 21, 2009 8:01 PM
Subject: Re: NFS- SAN - FreeBSD


Grant,

DAS = Direct-Attached Storage, sorry to be confusing.

I cannot personally speak to the performance of FreeBSD's NFS, but I wouldn't expect it to be the bottleneck in the situation described. Maybe others with more experience could chime in on this topic.

The way to use a DAS is to connect the DAS to a server with an external SAS cable (or two). The PERC6/E controller you would need inside the server is very well supported in FreeBSD. The DAS system would basically act the same as internal disks would act (in the case of the MD1000). Of course you'll want to check with Dell before you make any purchases to be positive that your hardware will all communicate nicely, as I'm no Dell salesperson.

Depending on how large of an array you plan to make (if larger than 2TB) you may have to investigate gpart/gpt to partition correctly, but that's quite simple in my experience.

Chris

Grant Peel wrote:
Chris,

Thanks for the insight!

I will defineately investigate that DAS ... although I am not (yet) sure what the acronym means, I am sure it is something akin to "Direct Access SCSI".

You are quite right, I would like to use NFS to connect the device to the 6 servers I have, again, it would be only hosting the /home partition for each of them. Do you know if there would be any NFS I/O slowdowns using it in that fassion? Would freebsd support (on the storage device) that many connections?

Also, do the Dell DAS machines run with FreeBSD?

Also, from you you explained, I doubt I really need the versatility of the SAN at this point, or in the near future. I simply want a mass /home storage unit.

-Grant

----- Original Message ----- From: "Christopher J. Umina" <chris.um...@studsvikscandpower.com>
To: "Grant Peel" <gp...@thenetnow.com>
Cc: <questi...@freebsd.org>
Sent: Tuesday, July 21, 2009 5:43 PM
Subject: Re: NFS- SAN - FreeBSD


Grant,

I mean to say that often times external SCSI solutions (direct attached) are cheaper and perform better (in terms of I/O) than iSCSI SANs. Especially if you're using many disks. SANs are generally chosen for the ability to be split into LUNs for different servers. Think of it as a disk which you can partition and serve out to servers on a per-partition basis, over Ethernet. That's essentially what an iSCSI SAN does. While DAS systems allow the same sort of configuration, they don't serve out over Ethernet, only SCSI/SAS.

Since you plan to use NFS to share the files to the other servers, I think it may make more sense for you to use a SCSI solution if yo don't need the versatility of a SAN.

Of course I know nothing of how you plan to expand this system, but from what I understand, with Dell DAS hardware it is possible to connect up to 4 different servers to the DAS and expand to up to 6 15 disk enclosures. The MD3000i (iSCSI) expands only to 3.

Another issue is that without compiling in special versions of the iSCSI initiator, even in 8.0-BETA2 (which is not production-ready), iSCSI performance and reliability are terrible. There are other versions of the code (which I currently use) for the iscsi_initiator kernel module, but unless you're comfortable doing that, you may consider DAS in terms of ease of implementation and maintenance as well.

Chris

Grant Peel wrote:
Chris,

I don't know what a direct attached array is.....

What I was just thinking was move all of the servers /home directory to a huge NFS mount.

If you have the time to elaborate fursther, I would apprciate it...

This iSCSI think has me entrigued, but I must admit I know little about it at this point.

-Grant

----- Original Message ----- From: "Christopher J. Umina" <chris.um...@studsvik.com>
To: "Grant Peel" <gp...@thenetnow.com>
Sent: Monday, July 20, 2009 11:27 PM
Subject: Re: NFS- SAN - FreeBSD


Grant,

I have to ask, is there a reason you're intent on going with a SAN versus a direct-attached array?

Chris

Grant Peel wrote:
Thanks for the reply.

I have not used/investigated the iSCSI thing yet....

The original question is can I just use an NFS mount to the storage's /home partition?

-Grant
----- Original Message ----- From: mojo fms To: Grant Peel Cc: freebsd-questions@freebsd.org Sent: Monday, July 20, 2009 4:21 PM
  Subject: Re: NFS- SAN - FreeBSD


You would be better off at least having the SAN on 1gb ethernet or even better tripple 1gb (on a 100mb switch should be fine but you need failover for higher avaliability) ethernet for latency and failover reasons with a hot backup on the network controller. I dont see why you could not do this, its just iscsi connection normally so there is not a big issue getting freebsd to connect to it. We run 2 of the 16tb powervault which does pretty well for storage, one runs everything and the other is a replicated offsite backup. Performance wise, it really depends on how many servers you have pulling data from the SAN and how hard the IO works on the current servers. If you have 100 servers you might push the IO a bit but but it should be fine if your not serving more than 2Mb/s out to everyone, the servers and disks are going to cache a fair amount of always used data.


On Mon, Jul 20, 2009 at 11:52 AM, Grant Peel <gp...@thenetnow.com> wrote:

    Hi all,

I am assuming by the lack of response, my question to too long winded, let me re-phrase:

What kind of performance might I expect if I load FreeBSD 7.2 on a 24 disk, Dell PowerVault when its only mission is to serve as a local area storage unit (/home). Obviously, to store all users /home data. Throug an NFS connection via fast (100m/b) ethernet. Each connecting server (6) contain about 200 domains?

    -Grant

----- Original Message ----- From: "Grant Peel" <gp...@thenetnow.com>
    To: <freebsd-questions@freebsd.org>
    Sent: Saturday, July 18, 2009 10:35 AM
    Subject: NFS- SAN - FreeBSD



      Hi all,

Up to this point, all of our servers are standalone, i.e. all services and software required are installed on each local server.

      Apache, Exim, vm-pop3d, Mysql, etc etc.

Each local server is connected to the Inet via a VLAN (WAN), to our colo's switch.

Each server contains about 300 domains, each domain has its own IP.

Each sever is also connected to a VLAN (LAN) via the same (Dell 48 Port managed switch).

We have been considering consolidating all users data from each server to a central (local), storage unit.

While I do have active nfs's running (for backups etc), on the LAN only, I have never attempted to create 1 mass storage unit.

      So I suppose the questions are:

1) Is there any specific hardware that anyone might reccommend? I want to stick with FreeBSD as the OS as I am quite comfortable admining it,

      2) Would anyone reccomend NOT using FreeBSD? Why?

3) Assuming I am using FreeBSD as the storage systems OS, could NFS simply be used?

4) Considering out whole Inet traffic runs about 2 Mb/s, is there any reason the port to the Storage unit should be more than 100 M/b (would it be imparative to use 1 G/b transfer)?

      TIA,

      -Grant

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