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malebolgia
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Good or Bad SCSI Pick For Server

Wed Jan 20, 2010 10:17 am

Long story short, I have a newly ordered Dell PowerEdge 2950 server that didn't get configured with any kind of SCSI support. So now I need to figure out the best and/or compatible format supported on this server. Looking over the Dell PDF for the system (please see the link below... page 76) it says:

The system is available with either a PCI-X or a PCI Express (PCIe) left riser board option. The PCI-X left
riser board provides two PCI-X 64-bit/133-MHz expansion slots, while the PCIe left riser board provides one
PCIe x8-lane expansion slot and one PCIe x4-lane expansion slot. The half-height center riser board
provided with both PCI-X and PCIe left riser board options features one PCIe x8-lane expansion slot. The
three expansion card slots are on separate buses.

There is more on page 76.. this just seemed to be the most useful.


I'm thinking the best SCSI card to get is a PCIe x4, but as I'm unsure I come here asking the web’s most knowledgeable hardware gerbils. 8)

PDF - Dell PowerEdge 2950 System
 
Norphy
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Re: Good or Bad SCSI Pick For Server

Wed Jan 20, 2010 11:28 am

The 2950s that we have here all have SAS Support. Do you really need a discrete SCSI card as well? Is it for a tape drive or something?
 
Dieter
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Re: Good or Bad SCSI Pick For Server

Wed Jan 20, 2010 11:39 am

I'm not sure how you can add it after it's shipped (Dell probably has a kit), but the integrated PERC 6i controller has worked well for us. Really it's just a RAID key (ROMB - RAID on Mother Board), some memory, and a battery pack. The drive controller built into the motherboard has RAID capabilities which are activated by the ROMB key.

We run anywhere from SAS 15k drives to 7.2k SATA drives (not in the same server!), and it seems fast enough. Nowhere near the speed of our SAN, but that is to be expected.

I don't have (much) experience with Dell's add-in PERC controllers (especially on the 2950's). Supposedly they are a little bit better than the integrated PERC 6i, but we have not needed it. If you have an external SAS/SCSI shelf, then you'll need the add-in cards.

PERCs are re-labeled MSI controllers, and are very good and easy to configure. I highly recommend them.

Also, what kind of drive configuration do you have? There are 3 or 4 backplane options, I think. 4x3.5" drives, 6x3.5" drives, and 6 (or maybe 8?)x2.5" drives. Then, you need to make sure you have the right drive caddy/carrier/sled for the drives that you have (SAS or SATA). You cannot purchase them separately from Dell, and they aren't cheap when you need a lot of them from 3rd party vendors.

Best option is to build the server from Dell the way you want it. It's MUCH cheaper than adding on later, and everything is ready to go. So, if you have the option of returning the server to Dell (they have a good return policy), I'd recommend doing that and custom building the server you want.

Also, Dell will not (fully) support 3rd party drives, even if you get the near-line SATA drives (RE4's, etc). Dell certifies their own drives, which are usually relabeled Seagates or Hitachis, but they DO add their own firmware, and they fully support that. We run mostly "Dell" drives, though we have added some RE3's in a RAID1 set on one server, and it has worked well, although the Dell monitoring utilities complain that they are not certified drives.

Good luck!
 
Dieter
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Re: Good or Bad SCSI Pick For Server

Wed Jan 20, 2010 11:44 am

Norphy has a good point. If you're just looking for external SCSI support to run a tape drive or something, then a good Adaptec controller should meet your needs. Check Dell's website for "parts for your Dell". They will often have 3rd party solutions that they have validated in the system. Sometimes more expensive, sometimes less.
 
malebolgia
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Re: Good or Bad SCSI Pick For Server

Wed Jan 20, 2010 12:52 pm

Norphy wrote:
The 2950s that we have here all have SAS Support. Do you really need a discrete SCSI card as well? Is it for a tape drive or something?

Sadly yes, old Quantum Tape device.
 
Norphy
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Re: Good or Bad SCSI Pick For Server

Wed Jan 20, 2010 3:58 pm

Well, in that case it won't make much difference if you get a PCIe or PCI-X card. A U320 SCSI controller won't saturate either bus and it's unlikely the tape drive will have much impact on the SCSI controller either!

Give your friendly Dell rep a call and get him to quote you on whichever SCSI standard you need. You may pay a bit more if you buy from Dell but at least you can be reasonably sure that the kit will work with your server and you have someone to shout at if it doesn't!

PERCs are re-labeled MSI controllers, and are very good and easy to configure. I highly recommend them.


Minor nitpick, they're actually rebadged LSI controllers, not MSI! In addition, they're not always LSI either. We have a few servers with Adaptec based PERCs as well.
 
Dieter
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Re: Good or Bad SCSI Pick For Server

Wed Jan 20, 2010 4:08 pm

Norphy,

You're right. I knew MSI didn't look right as I was typing it, but I was too lazy to look it up. As far as I've seen, Dell hasn't used Adaptec since the PERC3 days???

And I would definitely recommend that malebolgia go with a name brand SCSI adapter. I've had really good luck with Adaptec. They're expensive, but they work, and have wide support.
 
malebolgia
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Re: Good or Bad SCSI Pick For Server

Fri Jan 22, 2010 3:22 pm

Thanks for the help all, I've sent our Dell rep. an e-mail. I'm curious to see what parts he recommends. :)

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