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" <[email protected]>
To: "Grant Peel" <[email protected]>
Cc: <[email protected]>
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"
<[email protected]>
To: "Grant Peel" <[email protected]>
Cc: <[email protected]>
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"
<[email protected]>
To: "Grant Peel" <[email protected]>
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:
[email protected] 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 <[email protected]>
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"
<[email protected]>
To: <[email protected]>
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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