Swap in RAID1?

[Alma J Wetzker]

Michael Hipp wrote:
> Michael Hipp wrote:
> 
>> I've seen different answers to this question ...
>>
>> Should you have your swap partitions configured inside a RAID1 device 
>> or as separate standalone partitions?
>>
>> I've been hold that it'll crash anyway if you put swap in RAID and a 
>> drive fails. But won't it crash if you have two swaps and one goes away?
> 
> 
> Replying to my own post ...
> 
> From: http://www.linux-sxs.org/hardware/raid_for_idiots.html by our own 
> David Bandel
> 
> "Once your new RAID disk has been partitioned and all but the swap 
> partition are type Linux raid autodetect (fd), the hard part is done.  
> N.B. I chose not to RAID swap.  However you may if you like.  I kept two 
> separate swap partitions, one on each disk, for extra speed.  Your 
> choice, RAID if you like, but you'll take a slight performance hit."
> 
> Now if I could just find that comment I read somewhere that it'll crash 
> anyway even if you put swap in RAID. Seems wrong to me, but I'm still 
> learning.

Running on intuition, (which means I haven't a clue) I would say that putting 
swap on a hardware mirror would give you better performance.  Putting more 
spindles under your data gives you a chance to get to it faster.  Using 
software mirrors means the processor must manage the swap fs after it is 
trying to write memory to the disk, touching the data twice, ouch!

Off hand, I would say that the system would be pretty upset if it lost the 
swap drive, if it was using it.  As for crashing, that would depend on what 
went to swap.  If I lost a swap partition, I would want to bounce the box, 
just to make sure everything was clean.

     -- Alma