[sclug] RAID-1 on asymmetric disks?

[Tom Carbert-Allen]

although after trying all 8 in one machine, you again realise the 
bottleneck is the interconnect from flash to CPU
as did OCZ:
http://www.theinquirer.net/inquirer/news/293/1051293/ocz-1tb-ssd-raid-module
just waiting for availability now

Is it just me or has it been logical to put flash (or even more ram for 
that matter) directly on a PCI-E card since day one?

http://www.hyperossystems.co.uk/07042003/hardware.htm

even that seems limited by SATA bottleneck (not the wire speed, the chip 
that runs it on most motherboards, and certainly latency is higher 
because of it), why don't they just put them on PCI-E then we can all 
enjoy loading our entire OS and system partition into RAM.

When you use a RAMputer as I like to call them (16gb ram is enough), you 
realise the disk and it's interconnect is normally ALWAYS the bottleneck 
in most modern machines.

TCA

David Given wrote:
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> Alex Butcher wrote:
> [...]
>   
>> I doubt you'll encounter any problems. I do md RAID between partions
>> "all the
>> time"; I even tend to have a RAID0 paid and a RAID1 pair - the former for
>> 'disposable' parts of the hierarchy, like /tmp
>>     
>
> On a related topic, I'm mulling over the idea of making myself a DIY SSD
> out of USB thumb drives. They're approaching 1 UKP per GB these days,
> which makes them about half the price of a real SSD.
>
> As one of the key advantages of this technique is that adding capacity
> ought to be easy and cheap, I'm trying to figure out the best way of
> designing the system to allow this. Unfortunately as far as I can tell
> increasing the size of a RAID5 array looks to be rather hard, especially
> if the drives are different sizes. (Next year a 32GB flash drive would
> probably be the same price as a 16GB drive this year. No, I don't want
> to add this as two 16GB partitions.)
>
> Any suggestions of things I should look into? (Other than 'use ZFS', of
> course. I would if I could.)
>
> - --
> David Given
> dg at cowlark.com
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