what raid controller?

[Emanoil Kotsev]

--- On Mon, 10/13/08, James Gray <james at gray.net.au> wrote:

> From: James Gray <james at gray.net.au>
> Subject: Re: what raid controller?
> To: deloptes at yahoo.com, "Kubuntu Help and User Discussions" <kubuntu-users at lists.ubuntu.com>
> Date: Monday, October 13, 2008, 9:59 PM
> On 13/10/2008, at 5:10 PM, Emanoil Kotsev wrote:
> > I've been admistrating few companies with more
> than 200 employes and  
> > using software raid was the best choice.
> > I'm using it also at home and this year I've
> been testing software  
> > raid on external usb boxes.
> > The great advantage of linxu software raid over
> hardware one is also  
> > that mdadm utility do monitor your devices and if one
> fails you  
> > first get e-mail and second can easlily replace it.
> > Having a hardware raid you should look all the time at
> the leds if  
> > they light green, yellow or red.
> > The overhead by the raid layer is minimal and raid has
> been tested  
> > extensively so it's kind of production software
> but I always tend to  
> > say - use it at your own risk htough ;-)
> 
> 
> Before anyone slams the "reply" button in a red
> mist of rage, please  
> read the whole message :)
> 
> To make a blanket statement like "Having a hardware
> raid you should  
> look all the time at the leds if they light green, yellow
> or red" is  
> just plain nonsense.  You probably haven't played with
> real RAID  
> technology in a while ;).  I've managed systems with
> Dell PERC, Compaq  
> SmartArray, Adaptec and HP SAN technologies - under linux
> they *all*  
> have the ability to provide the admins with a number of
> notification  
> vectors from e-mail, "wall" right through to
> out-of-band SMS/Pager  
> alerts etc.

Ok I agree - my information status is about 6-5 years old. At this time SATA was not invented ;-) or at least not on the market and I was not talking about 200$ raid controlers.

We did at this time evaluation for two companies with about 200 employees each ... buying a hardware riad was pretty nosens as software raid with SCSI and even with IDE dirves gave satisfying performance.

We (my collegues and I) managed about 1TB of data (a huge amount at that time) on a Dell power edge and power vault as far as I remember.

I've just shared my experience (professional one) as there was a statment that it's kind of dangerous using linux software raid...

> 
> I don't disagree with anything else you've said,
> and I assume that in  
> the context of systems outside a corporate budget, the type
> of  
> hardware RAID controllers available can be somewhat cobbled
> versions  
> of their bigger siblings.  However, even the low-end
> Adaptec SATA RAID  
> controllers (as in REAL RAID, not their fake-RAID cousins)
> can still  
> notify admins about drive failures - via "ASM" :)
>  The Adapatec  
> 2405[1] is a nice little hardware RAID controller (PCIe x8)
> that has  
> notification and hot-swap capabilities etc. and generally
> wont break  
> the bank (approx USD$200).

this was a useful update of  my knowledge

> 
> Like most things in life, you get what you pay
> for....unless you're  
> installing Linux, in which case you generally get a whole
> heap more :D
> 


what should I say ... don't have time  to read this thread - think sharing experience is good enough.

since then I don't see any reason for buying or using hardware raid.

I have now about 1TB at home(office) 2IDE inside an old 500MHz pc acting as server 2 IDE in a usb box and 2 SATA in usb box outside. Took me about 6 months to get a working kernel for this, but since few months it's working like a charm. Now I have to buy new boxes and drives because the disks are almost full ... 

Did I mention the raids are encrypted :-P - this is the only thing that's a bit fuzzy in matters of cpu usage

So adding a layer in between is not a problem ... unless you let a hole army of rats crawl on it.

regards