[Wolves] RAID on 750mhz processor?

[James Turner]

On Saturday 07 October 2006 02:10, leo sandhu wrote:
> Hi guys,
>
> Slowly I seem to be inching my way towards retrieving at least some of my
> dads lost data.  Thus far I have 30gb of junk to sift through :(
>
>
> In an attempt to prevent a repeat occurance and also provide better access
> to data, I have convinced my dad that what he really needs is a fileserver
> that he can access when out and about..
>
> I am hoping to use an old pc we have just retired from service.  It has an
> Asus K7V motherboard and a K750mhz cpu with onboard RAID controller.   The
> plan is to go for basic mirroring and then set the server to use storage
> quotas and authentication.  Hopefully, the only problem will be that I have
> never configured RAID before.
>
> Will 750mhz be sufficient to handle a couple of 300gb drives, kernel 2.6, a
> thin debian install and still operate smoothly?
>    The few things I have read recently suggest that I could have problems
> with the read-write process being slowed by fragmented data if the cpu not
> sufficent.

Although your specific load/performance requirements should be taken into 
account, I'd have thought that the above spec would quite adequate for a 
basic file server. CPU performance shouldn't be significant for disc 
mirroring, but is more relevant for RAID5 and other configurations that 
involve performing parity calculations as data is written. The more RAM you 
can pack in the better, as this will allow performance to be improved via 
caching.

Are you thinking of using the Linux kernel RAID ("md" - multiple device) or 
the RAID provided by the motherboard BIOS? As a general rule, I'd strongly 
favour the former, on the grounds of:

 - Open, standardised, vendor-netural on-disc data structure allowing discs
   to be transfered between machines/motherboards if needed.
 - More versatility than most hardware controllers. Operates on individual
   partitions rather than entire discs.
 - Some hardware controllers prevent the correct operation of SMART monitoring
   and other diagnostics operating on invididual discs in the array.

Many onboard controllers in consumer motherboards rely on a device driver to 
implement the RAID functionality using the host CPU, rather than 
hardware-based parity calculation as would be found in server-class 
controllers. (i.e. they are actually software RAID anyway)

Regarding fragmentation, were the comments you read made in the context of 
Linux file servers? I doubt it'd be a significant issue for a home server 
unless the discs were nearly full (often quoted as >95%) and/or had an 
unusual usage pattern that prevented optimum arrangement of data. I suspect 
that such warnings are likely to be more applicable to Windows, or to 
machines that have a continuous "churn" of data such as busy mail/news 
servers.

Regards,

James