[ale] Onboard RAID

[Greg Clifton]

Well, we have a contract for this system and got hit by the recent hard
drive price increase, so we don't have any more $ to spend on an additional
box (and it wasn't my sale or I might have pitched a FreeNAS box). Plus we
have mucho surplus redundant power in this box. Surely RAID support under
Server 2008 is way better than running a [I think] non raided NT drive that
has been running for years now?

Now as I understand it, all the BIOS options are "fake RAID" and I fully
appreciate the potential for problems with a [bootable] hardware RAID. I
always recommend that my customers have a separate mirrored boot drive and
NOT boot from the storage array. I suppose the same sort of problem could
result from booting from the fake RAID. The next question is, if it is so
bad/unreliable, WHY do the BIOSes support the fake RAID in the first place?
Especially now that we have 3TB and soon will have 4TB hard drives--that
pretty much does away with the need for RAID for capacity needs for most
folks, though there is still a demand for striping for faster data access.

On Wed, Nov 16, 2011 at 2:28 PM, Michael B. Trausch <mike at trausch.us> wrote:

> On 11/16/2011 02:12 PM, Greg Clifton wrote:
> > More details this is a new server (Single Proc Xeon X3440) with only 10
> > users, so it won't be heavily taxed. Moving the storage to a different
> > Linux box really isn't an option either. We're replacing an OLD server
> > running NT with the 2008 server.
>
> Depending on the reason why it "isn't an option", it might be worth
> pushing back on.  The whole point of separating it out is because
> Windows server sucks, even with only 10 users on it.  The way it
> operates sucks, the way it treats things on the disks sucks, the overall
> speed of data access sucks.  Keep a single disk in the Windows server
> (maybe mirrored) that is the system disk, and put everything else
> somewhere else.  Don't want a Linux box, then get a RAID array box that
> hooks up to the Windows box with a single eSATA connection and call it a
> day.  That is better than having Windows sort it out.
>
> > What you are saying is that SOFTWARE is "more better" in all cases than
> > the BIOS based RAID configuration. OK, but does Server 2008 support RAID
> > 10? If not, we must rely on the BIOS RAID.
>
> And you do NOT want to rely on BIOS RAID.  At all, period, never.  Bad
> idea, bad call.  I have seen *many* BIOS RAID setups fail for a wide
> variety of reasons, but most of the time it seems to me that it is
> because some component of the implementation of them is buggy.  It
> happens frequently enough that I wouldn't trust hourly snapshotted data
> on such a storage mechanism, I'll say that much.
>
> > If we must do that then the question falls back to which is the better
> > RAID option [under Windows].
> > I saw something on some RAID forum that said the Adaptec was for Linux
> > OS and the Intel for MS OS. Since Adaptec drivers are built into Linux,
> > that at least makes some sense.
>
> Adaptec has drivers for Windows as well.
>
> The thing is that with hardware RAID it doesn't matter: you cannot
> upgrade, you are not portable.  It is a dangerous option.
>
> Consider this:  what happens if your disk controller fails?  If that
> disk controller does RAID, and it has been discontinued, you may be
> looking at a whole RAID rebuild instead of just a hardware swap-out.  In
> other words, with hardware RAID, it's far more likely that an outage is
> going to last forever because you'll have to start over and rebuild the
> array, restoring data to it.
>
> If the thing that fails is a box running Linux with four disks in it,
> you replace the box and move the disks over and you're done.  If you
> have a spare box on hand, you can be up in ten minutes.
>
> If you *are* going to go the hardware RAID route, make sure you have a
> spare, identical controller in stock in case of failure.  I've seen it
> happen where RAID controllers were incompatible after seemingly minor
> changes (device F00e vs. F00f might be two completely different things,
> same for F00e and F00e+) to the model number.
>
> And just don't use fakeraid (that is, BIOS provided RAID).  It is simply
> not a viable option if you like uptime and robustness.
>
>        --- Mike
>
>
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