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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