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Looking at getting some Dell Workstations (T3500). One of the options is to raid 1 the harddrives (presumably this would give you a speed boost). Is this software or hardware raid?

jimconstable
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  • Possibly a speed boost for reads depending on what the controller supports. For RAID 1 I'd be more interested in the failover capability since you can lose a drive and keep right on working. When a replacement is available, pop it in and it will rebuild the new drive and keep right on humming along. – Justin Scott Jun 14 '09 at 07:11

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http://www.dell.com/us/en/business/desktops/workstation-precision-t3500/pd.aspx?refid=workstation-precision-t3500&s=bsd&cs=04

"The T3500 uses an integrated SATA 3.0Gb/s host controller (part of the Intel chipset) and supports host based RAID 0, 1, 5, 10, an optional PCI-e SAS 6/ir controller supports SAS drives with host based RAID 0 or 1."

Hardware RAID I'd say.

kashani
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  • I concur, hardware RAID. I have an older Dell workstation at home with hardware RAID 1 and it's worked without any trouble for going on six years. – Justin Scott Jun 14 '09 at 07:09
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Dells newer servers all have decent enough raid setups in Hardware. Generally only when you start looking at raid 10 or 01 that is becomes an issue. Some of their older cards were using tricks to get to a raid 10 level meaning losing a drive didn't always work as it should.

The T3500 does use HW raid on setup which is fine in a workstation. Monitoring for failures is easy enough in this situation.

Ryaner
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You absolutely have to look at the raid card specifications, especially for Dells. For example, I have a 745N storage server that has possibly the worst RAID card imaginable. I get a mere 2MBps out of it using some large file copies when I had it in a 4-drive RAID5 (the default). Switching it to a JBOD configuration with RAID5 in software and I get 20MBps. Still not fantastic, but a whole lot better. Searching google it appears lots of other people have the same problem.

Sometimes RAID cards are little more than BIOS tricks to write the same data twice. This is especially common in workstation motherboards. It may have been a good thing once upon a time, but as CPUs are insanely fast and RAID calculations are quite easy, you'll only see a minor load on your CPU (my server that uses raid1 sees a 1% additional load on average)

The easiest way to check is to try it - large file copy using your RAID card, and again using software RAID. See what's faster. If you don't have this luxury, find the type of RAID chip that is being used and search for it - you'll quickly find out whether its a so-called 'fakeraid' or real raid card (ie one that has its own dedicated processor). Toms Hardware will often have benchmarks, and the linux raid driver page has a list of 'fakeraid' chips.

Looking at the spec (and a quick google), x58 chipset is a fakeraid controller.

No doubt if Dell is building the system, it'll be the BIOS option to raid the disks. I'd go without. You can set 2 drives up in RAID1 after installation using Windows (or Linux) software raid. You might be able to set it up after-installation in the BIOS, but I'm not sure about that option.

gbjbaanb
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  • For my own education, do you have a link that discribes in detail the differences in real raid vs fake raid? I read how the linux page describes the differences and I don't completely agree with it. While I do agree that the true hardware raid is better, I don't know that I'd consider a raid card that "OS driver and card's on-board flash BIOS provide 100 percent of the RAID capability" a software raid, to me this is more of a hybrid. I'd consider a software raid one where you are only using a standard card (no raid) and build the raid completely with the OS – SpaceManSpiff Jun 14 '09 at 14:22
  • I'm going to answer my own comment on this. From the Wikipedia RAID page, it does a better job describing the 3 types of RAID. Adaptec calls them HostRAID. So while not as good as Hardware RAID, I think this is better then software raid where the OS is controlling everything, you still get the advantage of it looking like a RAID to the OS at the BIOS level. Making a nice compromise between the two. – SpaceManSpiff Jun 14 '09 at 14:50
  • If it's fakeraid, it's software raid, as far as performance goes. All the chip does is tweak the bios so that, given the right drivers, it'll see some init info. But the driver does all the raiding in software. If you're running Windows, I don't know that you have a lot of choice. I've done this a fair amount on workstations and the result is definitely mediocre at best. When there is an issue, it's fragile to get back to reliability. If you're running Linux, I would do all the raiding manually with LVM and the md driver. – Steven Parkes Jun 14 '09 at 15:24
  • Good point actually. I'm not a fan of software RAID *at all* but at least you know where you stand with it, as opposed to "is it real or is it fakeraid" hardware. – Rob Moir Jun 14 '09 at 18:09
  • This is interesting, I haven't had an issue thus far and I hadn't been aware of the differences so I expect some of my RAID setups' have been the BIOS based ones. I can't say I've had any issues though and I test the machines before moving them into production by removing one of the drives while its running just after the OS is installed and then re-installing it the next day. No issues that I've noticed but I'll need to go back and see if these were BIOS RAIDs. Lower load servers so speed wasn't an issue for me. I'll watch for this in the future though, good to know. Thanks. – SpaceManSpiff Jun 15 '09 at 00:04
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We have discussed a similar question so here is a direct link to answer your question.

See these related topics too:

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cstamas
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Speed isn't a reason to specify RAID1 - any gains in one area are likely to be offset by losses in another area making the overall improvement hard to measure. If you need reliability, that would be a reason to go with RAID1.

Rob Moir
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Get the Perc 310 controller at the very least. The onboard is effective, but less than ideal, I've had trouble with that configuration often. The 310 uses the system processor to perform. The best choice from the factory is to get the 710, which uses it own processor and operates completely independent from the system processor. Beefy and fast, a good choice if you are processing lots of video or other very large files.

Craig
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