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Re: IDE Raid Controller concerns

Am Mittwoch, 15. Oktober 2003 00:12 schrieb Chris G.:
> I've got a couple questions related to IDE raid that if I could get some
> feed back on, I would really appreciate it.
> A little bit ago, we suffered from a single drive (in software raid 5)
> causing data corruption and poluting the array before being ejected.  This
> made almost all the data on the raid invalid and unusable.  We knew that
> this was probably going to happen sooner or later, but I started wondering
> about hardware based raid cards, and if they would handle this any better.
> I'm looking at a raid to have a 12x120 gig 7200 RPM ide drive setup.  11
> drives in the array, and the 12th drive as the spare.
> Controller wise we are looking at the 3Ware Escalade 7506-12 card, but I
> have never seen this card in action, and I have no idea how it might
> handle the above problem.
> If any of you have used this card, what have your thoughts been?  What
> problems did you run into?  Do you recommend a different card in the same
> price range ($400 to $600)?
> Thanks for any help you might be able to offer.
> Chris G.

Hi Chris and all,

Yes , the 3ware will do the job,  we got  two 7506-12's running in NAS-boxes  
for 3 (respectively 5) months without troubles so far, and I have used many 
more of their smaller modells with good results. The 3wares tend to feel 
sluggish (big time)  when rebuilding an array under load, but don't they 
all...? I haven't had one fail during rebuild so far.
Otherwise, they are my choice for IDE raid, good drivers, good web-gui, good 
performance, reasonable phone support, what else?
Like I noted some time ago, we've had issues cold-booting from them in Intel 
chassis w/onboard Promise controllers.
I don't really like the idea of working disks outnumbering hotspare 11:1, do 
you? I would much prefer 10:2, simply because the fact that if one disk out 
of a certain production lot goes boom, why shouldn't the others follow soon? 
This gets more likely as numbers increase. However, unless you don't already 
own the 120 GB disks, why not use 7 x 200GB disks? You'd get the same 
capacity but with fewer disks (heat, power, noise..), at practically the same 
cost (WD 1200JB @94 EURO over here, WD2000JB @160 EURO), you would still have 
5 IDE channels left to populate later as need arises on the 7506-12, or you 
could even get by with a 7506-8 and a smaller case, which would save another 
$150 or so (spend them on disk #8 => use 2 spares, or go wild and use 8 disks 
in a 2 x (3+1) configuration, which will be faster in most situations, even 
when run  on one controller). Either solution would pretty much max out one 
PCI bus anyhow, even on 64 Bit boards.
The advantages that usually come with using many spindles are marginal IMO 
when using relatively slow IDEs, as compared to 15k SCSIs - you're not 
thinking of putting that monster-database with 100's of users on this array, 
or any other situation with lots of concurrent reads and writes, are you? 

Bulk transfer rate will up there with the best of them, but avg. seek time 
won't, which I guess, most people on a budget are willing and able to accept. 

So it's 'yeah, go ahead, the 3ware will be ok'.
Don't know about any other controllers in this segment, I only know 2 channel 
Promise or Highpoint - and I really hate them, they are only 'sort of raid'.
I think they don't even have any intelligence onboard, so where's the point or 
the big difference to software raid?

Jochen Rosenbauer

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