OT 2nd posting pci ata card ??

Dave S ubuntu at pusspaws.net
Sun Apr 2 07:32:18 UTC 2006

> I would highly recommend changing to a hardware RAID IDE card.  The
> downside to this is that I am not certain that you will not need to
> re-install in the process of moving the drives from software RAID on the
> MB to the hardware RAID on an add-in card.  It may work, but I would not
> hold my breath.

I suspect its a (sob) re-install. I googled for comparisons of hard vs soft 
RAID and could not get a definitive answer. 

As a soft raid there is a performance boost on reading but I do not know how 
to quantify it. hdparm -tT just does not mean anythin on RAID. 

On soft raid I get system emails if a HDD goes out of sync / down - do you get 
a BIOS message if this happens in hardware RAID ?

> The biggest benefit of hardware RAID will be in performance.  You will
> get the speed increase of being able to read from mirrored disks, the
> reliability of having the two drive system, and the write speeds won't
> have the overhead of software needing to perform two separate writes,
> the hardware will take care of it.  In all, if you are adding a card, it
> is wise to move the RAID functionality into hardware.

I am not trying to start a flame war but does anyone have hard / soft RAID 
comparison's figures. How much slower is soft RAID ? If its marginal I wont 
re-install, if its significant I will stock up on coffee :)

> One side effect from this, if it is not already, the swap partition will
> also be RAIDed.  Since the RAID is in hardware, the drives will have to
> be true mirrors.  It is a good idea to have the swap in RAID for system
> reliability anyway, but as was discussed in a previous thread, some
> people do not mirror swap because of the write performance issues.  Once
> the write is in hardware, this is no longer as big an issue.

Ahh read a thread on this one, swap already RAIDed.

> I am running on a laptop, so I don't have any suggestions for the exact
> card.  I hope to do a desktop install soon, but that could still be a
> ways off.  I have a really old computer (Pentium MMX) that I'll be doing
> the install on, so I am watching this thread for ideas as to what
> hardware I will want to upgrade to also.
> -Matt



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