Re: Cheapest "software" RAID card
Hi,
On 24.10. 16:46, Jason Lim wrote:
> I have been investigating cheap "software" or "host-based" RAID cards.
> They tend to be magnitudes cheaper than real hardware RAID cards like
> 3ware/AMCC. But for some purposes, you don't care about the CPU overhead,
> but do want something hardware (not md software raid) especially when your
> on-board controller is crap.
Sorry for not directly answering your question, but I would like to bring
another point to your attention.
Cheap RAID cards usually don't have their own RAID logic on-board but
rely on the driver (i. e. a piece of software) to perform their duties.
So nothing gained here. Nevertheless, they usually have their own
on-disk format for the RAID metadata. Now what do you do, if your card
dies a year after purchase? In my experience it is a characteristic of
cheap hardware that it gets changed over time by the manufacturer (new
chip revision, firmware or other slight "improvement") and the exact
same thing is not available even a few months later. It is well
possible that the metadata format has changed. A card from a different
manufacturer will most likely have a different metadata format. Your
disks will become unreadable to you, your data is lost.
You can still use cheap "RAID" cards as disk controllers and implement
the RAID functions via the Linux md drivers.
Sincerely,
uLI
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