A general Raid 5 question

A general Raid 5 question

[Raz Ben-Jehuda(caro)]

If I pull the plug out from my machine while io is being generated. 
Is there a chance that  i would loose the raid ( obviously i would
loose some data).
I am refering to raid with no backup battery unit or anything of that sort.

I tried to do it and the worst case was that the rebuilding was long (
both in software raid and hardware raid -- 3ware ).

I would appreciate answers
Raz.

Re: A general Raid 5 question

[Clemens Schwaighofer]

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On 06/23/2005 02:31 AM, Raz Ben-Jehuda(caro) wrote:
> If I pull the plug out from my machine while io is being generated. 
> Is there a chance that  i would loose the raid ( obviously i would
> loose some data).
> I am refering to raid with no backup battery unit or anything of that sort.
> 
> I tried to do it and the worst case was that the rebuilding was long (
> both in software raid and hardware raid -- 3ware ).
> 
> I would appreciate answers

I have several hardware raid5 and one sw raid5 and I never had any kind
of issues during my initial test. Although I haven't had a poweroutage
to the box (well you should have UPS in front anyway), I had two other
lockups (some netaltalk issues) but the raids stayed all very fine.

-- 
[ Clemens Schwaighofer                      -----=====:::::~ ]
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Re: A general Raid 5 question

[Neil Brown]

On Wednesday June 22, raziebe@gmail.com wrote:
> If I pull the plug out from my machine while io is being generated. 
> Is there a chance that  i would loose the raid ( obviously i would
> loose some data).
> I am refering to raid with no backup battery unit or anything of that sort.
> 
> I tried to do it and the worst case was that the rebuilding was long (
> both in software raid and hardware raid -- 3ware ).
> 
> I would appreciate answers

"Pulling the plug" can cause physical harm.  It  probably isn't
common, and probably only affects cheaper hardware, but it can happen.
Electrical spikes or other sudden changes may not be what the device
was designed to handle.

If you pull the plug and hurt two drives of a raid5 array, you lose.

So yes, it can happen.  But is less likely to happen with better
quality components.
Possibly the old adage "RAID doesn't replace backups" applies.

NeilBrown