DELL RAID and Technet Question

_Kaiser_

Hey all,

I've recently bought myself a DELL Precision T3400 Workstation/PC that has now become my primary gaming rig (after I moved the Radeon HD5770, the upgraded PSU and a few other bits from my other PC)

This then leaves me with a Precision 390 with 8GB ECC RAM, 3x 1.5TB SATA HDDs and a Q6600 Quad CPU

What I want to do is set this up as a home network Domain Controller, Media (MP3s and video) storage and share server, and test box for myself

I have a Technet Plus sub (or whatever they call it now ) so I've installed Server 2008 R2 with the idea of setting it up as follows:

- Physical host:
Server 2008 R2, 2GB RAM, 750GB HDD - AD/DC, DHCP, DNS

- Virtual Server 1:
Server 2008 R2 (or maybe Windows Home Server?), 2GB RAM, 1.5TB HDD - Media store/share

Virtual Server 2:
Server 2008 R2, 2/4GB RAM, Remaining Disk - Testing purposes (I want to start messing with AD, ISA, Exchange etc with a view to doing the exams rather than just as part of my day-to-day job)


But as always there's a few problems...

The onboard Intel RAID chip won't recognize anything over 2TB for a RAID volume (which I gather is a BIOS limitation), so I just created 2 RAID 5 volumes over the 3 disks - 1 750GB for the OS/Host, and the rest for what will be the 2 Virtual Machines... this seems ok

The problem is that once I get 2008 R2 installed and setup as a DC, performance dies.. and I mean crawls!!! Constant disk accessing and the OS stalls while it does.
I'm assuming this is because the onboard RAID chip isn't up to the task/the size of the disks I'm using? (bearing in mind this PC is about 4/5 years old when TB disks were still a fantasy for most people)

- Would a dedicated DELL PERC card help? If so, which one should I go for?

- Anything else that might account for the problems?
For testing I set it up as standard non-RAID drives and it works fine (these are all brand new Samsung HDDs btw) so that's why I think its the onboard RAID chip that's the problem

Any advice appreciated!

On another note, my technet sub will soon expire - anyone have any discount codes that work on the IE site?

Cheers!

swampgas

Kaiser2000 wrote: »

But as always there's a few problems...

The onboard Intel RAID chip won't recognize anything over 2TB for a RAID volume (which I gather is a BIOS limitation), so I just created 2 RAID 5 volumes over the 3 disks - 1 750GB for the OS/Host, and the rest for what will be the 2 Virtual Machines... this seems ok

To be honest it's hard to say what the problem might be, but maybe RAID5 is an issue? http://www.miracleas.com/BAARF/BAARF2.html
You could install IOmeter http://www.iometer.org/ on the host OS and also the guest VM and do some IO testing to see what kind of performance you are able to get.

_Kaiser_

After a bit more testing, I think the problem does indeed lie with the onboard RAID chip/controller not being able to handle the setup as when the drives are setup as RAID 0 or 1 or just standalone "normal" drives all is well.

I may invest in a dedicated PERC card I think if I want to get this working - actually, would that get me around the 2TB Volume limit or am I still tied to that as a result of the BIOS?

swampgas

Kaiser2000 wrote: »

After a bit more testing, I think the problem does indeed lie with the onboard RAID chip/controller not being able to handle the setup as when the drives are setup as RAID 0 or 1 or just standalone "normal" drives all is well.

I may invest in a dedicated PERC card I think if I want to get this working - actually, would that get me around the 2TB Volume limit or am I still tied to that as a result of the BIOS?

As this server is just for home use, you could just skip using RAID altogether and take your chances! And keep an external backup of anything you don't want to lose (which you do anyway, right? )

POE101

Did you ever sort this out?

And can you (or anyone) shed some light in my darkness..

I have just got my hands on an old Dell Precision 390 and I'm interested in sticking two large 2 or 3Tb drives (along side existing 80Gb drive for OS) in it with raid as a Home Network File Server (running under Ubuntu Linux) and using wake on lan.

As far as I can see the onboard SATA is SATA I and the large drives are likely to be SATA II or III. I hadn't heard of the PERC card (so going to read up on it) but was wondering if a PCI controller card with internal SATA III ports would perform or be limited by the PCI bus speed (what ever it is)?

Also I am wondering if the stated 2Tb storage limit (as per 390 documentation) is in any way relevant if I do use a PCI SATA III controller?

_Kaiser_

Well I can tell you that 2 mirrored disks (RAID 1) will be fine but any more than that (as per my original post) and it becomes unusable if you try RAID 5 - this is using the onboard controller/RAID BIOS of course

With disks over 2TB you'll be limited by the BIOS and will have to split them into smaller virtual disks to see all the space. What I did was create a small disk for the boot drive (C) and then used Windows to combine the rest into a large second drive (D)

That said if you use the 80GB as your OS drive you SHOULD be ok using the rest for data as you describe but I never tested that and I know nothing about Linux or its requirements/limitations

The 390 is a great machine and will work fine subject to these limitations but in the end I ended up getting a PowerEdge 2950 very very cheap that I now have 4 (with plans for 2 more) 1.5TB disks in and it's excellent

POE101

Thanks for the response.

I will have a second 80Gb and plan to set up RAID1 on the pair. It looks like I can get a PCIe SATA II or III controller and simply add 2 larger 3Tb disks in various raid configurations. - even if the 2Gb limit still imposes itself, I think I can do as you say and set up smaller partitions. Linux supports hardware and software raid but unless I spend big money on the PCIe controller it looks like I will be using software raid but it is not a huge overhead on the CPU. Apparently most of the cheaper controller cards that claim to be hardware raid controllers use the system's CPU. Also with Linux its necessary to do some investigation to ensure the chosen hardware is tried and tested though this is becoming less and less of an issue.

At the end of the day I could have a 3Tb (or 6Tb with no redundancy) fast NAS server for around 200 euro to replace my aging, slow 500Gb one that cost around the same . If/when I get it all working I will post back.

Sparks

Avoid those onboard RAID controllers, they're usually referred to as FakeRAID for a reason

Also, you're better off with software RAID 10 than fakeware RAID5, especially in the event of a controller failure (because if your onboard fakeraid controller fails, you're just not going to get an offboard controller that can step in and replace it like nothing happened). Besides, with RAID10, you're effectively avoiding the whole "second disk dies during rebuild of first failed disk" nightmare, and you're not taking a massive performance hit. You do pay for it in disk space (because your RAID disk space is 50% of your total physical hard drive space) but that's the nature of RAID...