What happens with a Raid 5 when the controller fails?

On Jan 21, 5:27 am, Odie Ferrous <odie_ferr... RemoveThis @hotmail.com> wrote:
> Folkert Rienstra wrote:
>
> > Robert Wegner wrote innews:YtSdnTQnaZtoQA7anZ2dnUVZ8s6inZ2d@giganews.com
> > > Hi there,
>
> > > i've got an old storage server here, running W2k, with a promise pci-card
> > > raid controller. The controller hosts a raid 5 array and it is 4 or 5 years old,
>
> > > so i guess it isnt built any more.
>
> > Right, why check if you can guess, right?
>
> > > So, i wonder, what if the controller fails and i can't buy exactly the same
> > > one? Can i simply build in any new raid5-capable controller-card?
>
> > Sure, why not?
>
> > > Or does the  controller has to be compatible in some way (to the old card)?
>
> > Nope.
>
> > > Or is the data lost?
>
> > Very likely.
>
> Not at all likely, actually.  But your answers are always designed to be
> helpful and sympathetic, aren't they, Folkert?
>
> Rob - any reputable data recovery company should be able to recover your
> array without any problems.
>
> > Which is why you have backups that you can roll back.
>
> > > Thanks and best regards, rob
>
> Duncan
> --
> Retrodatawww.retrodata.co.uk
> Globally Local Data Recovery Experts- Hide quoted text -
>
> - Show quoted text -

RAID 5 is a standard http://en.wikipedia.org/wiki/RAID Therefore it
will not be hardware dependant and so someone will always beable to
recover the data

Michael
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

Folkert Rienstra wrote:
>
> Robert Wegner wrote in news:YtSdnTQnaZtoQA7anZ2dnUVZ8s6inZ2d@giganews.com
> > Hi there,
> >
> > i've got an old storage server here, running W2k, with a promise pci-card
> > raid controller. The controller hosts a raid 5 array and it is 4 or 5 years old,
>
> > so i guess it isnt built any more.
>
> Right, why check if you can guess, right?
>
> > So, i wonder, what if the controller fails and i can't buy exactly the same
> > one? Can i simply build in any new raid5-capable controller-card?
>
> Sure, why not?
>
> > Or does the controller has to be compatible in some way (to the old card)?
>
> Nope.
>
> > Or is the data lost?
>
> Very likely.

Not at all likely, actually. But your answers are always designed to be
helpful and sympathetic, aren't they, Folkert?

Rob - any reputable data recovery company should be able to recover your
array without any problems.


> Which is why you have backups that you can roll back.
>
> >
> > Thanks and best regards, rob


Duncan
--
Retrodata
www.retrodata.co.uk
Globally Local Data Recovery Experts
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

On Jan 21, 2:43 pm, Arno Wagner <m....TakeThisOut@privacy.net> wrote:
> Previously Robert Wegner <rob....TakeThisOut@gmx.net> wrote:
>
> > Hi there,
> > i've got an old storage server here, running W2k, with a promise
> > pci-card raid controller. The controller hosts a raid 5 array and it
> > is 4 or 5 years old, so i guess it isnt built any more.  So, i
> > wonder, what if the controller fails and i can't buy exactly the
> > same one?  Can i simply build in any new raid5-capable
> > controller-card? Or does the controller has to be compatible in some
> > way (to the old card)?
>
> The problem is that the RAID superblock is not standardized and hence
> it it unlikely to work with a different controller, unless the
> manufacturer specifically claims compatibility with your present
> controller. In fact not even the place the RAID superblock is found
> in, is standardized. That is also the reason why, when using hardware
> RAID, you should have a spare controller of the same model.
>
> > Or is the data lost?
>
> RAID5 is easy to recover for professionals. There is also an other
> option: dmraid (part of Linux software RAID) can assemble and use
> arrays from several different fake-RAID (software-RAID on a card,
> which is likely what you have) controllers. This may allow imaging the
> RAID under Linux, regardless of filesystem on it.
>
> My advice is to replace the controller after a full backup and
> to recreate with a new controller, of which you get two in
> order to have redundancy. Or to move to software-RAID, which does
> not have this limitation.
>
> Arno

Have I got the wrong end of the stick, but Superblock is a Unix term,
and not Windows?

I have 'struggled in the past with Unix disks as they all seem
different relating to superblocks etc.

The question though relates to W2K server - is Superblock relevant
here?

Again, please tell me if I am wrong, but I always thought a RAID disk
logically looked like normal big disk that just happens to be fault
tolerant.

Michael
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

Previously Robert Wegner <robweg DeleteThis @gmx.net> wrote:
> Hi there,

> i've got an old storage server here, running W2k, with a promise
> pci-card raid controller. The controller hosts a raid 5 array and it
> is 4 or 5 years old, so i guess it isnt built any more. So, i
> wonder, what if the controller fails and i can't buy exactly the
> same one? Can i simply build in any new raid5-capable
> controller-card? Or does the controller has to be compatible in some
> way (to the old card)?

The problem is that the RAID superblock is not standardized and hence
it it unlikely to work with a different controller, unless the
manufacturer specifically claims compatibility with your present
controller. In fact not even the place the RAID superblock is found
in, is standardized. That is also the reason why, when using hardware
RAID, you should have a spare controller of the same model.

> Or is the data lost?

RAID5 is easy to recover for professionals. There is also an other
option: dmraid (part of Linux software RAID) can assemble and use
arrays from several different fake-RAID (software-RAID on a card,
which is likely what you have) controllers. This may allow imaging the
RAID under Linux, regardless of filesystem on it.

My advice is to replace the controller after a full backup and
to recreate with a new controller, of which you get two in
order to have redundancy. Or to move to software-RAID, which does
not have this limitation.

Arno
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

Odie Ferrous wrote in news:47942D3F.8FEDF010@hotmail.com

> Folkert Rienstra wrote:
> >
> > Robert Wegner wrote in news:YtSdnTQnaZtoQA7anZ2dnUVZ8s6inZ2d@giganews.com
> > > Hi there,
> > >
> > > i've got an old storage server here, running W2k, with a promise pci-card
> > > raid controller. The controller hosts a raid 5 array and it is 4 or 5
> > > years old,
> >
> > > so i guess it isnt built any more.
> >
> > Right, why check if you can guess, right?
> >
> > > So, i wonder, what if the controller fails and i can't buy exactly the
> > > same one? Can i simply build in any new raid5-capable controller-card?
> >
> > Sure, why not?
> >
> > > Or does the controller has to be compatible in some way (to the old
> > > card)?
> >
> > Nope.
> >
> > > Or is the data lost?
> >
> > Very likely.

> Not at all likely, actually.

Gee, not at all, Odiferous?

> But your answers are always designed to be
> helpful and sympathetic, aren't they, Folkert?

Like yours are, Odiferous.

> Rob - any reputable data recovery company

Now what does that say about you, Odiferous?

> should be able to recover your array without any problems.

Which Odiferous just offered to do for free, right, Odiferous?

>
> > Which is why you have backups that you can roll back.
> >
> > >
> > > Thanks and best regards, rob
>
>
> Duncan
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

Arno Wagner wrote in news:5vjpclF1mv66iU1@mid.individual.net
> Previously Robert Wegner <robweg.TakeThisOut@gmx.net> wrote:
> > Hi there,
>
> > i've got an old storage server here, running W2k, with a promise
> > pci-card raid controller. The controller hosts a raid 5 array and it
> > is 4 or 5 years old, so i guess it isnt built any more. So, i
> > wonder, what if the controller fails and i can't buy exactly the
> > same one? Can i simply build in any new raid5-capable
> > controller-card? Or does the controller has to be compatible in some
> > way (to the old card)?
>
> The problem is that the RAID superblock is not standardized and hence
> it it unlikely to work with a different controller, unless the
> manufacturer specifically claims compatibility with your present
> controller. In fact not even the place the RAID superblock is found
> in, is standardized. That is also the reason why, when using hardware
> RAID, you should have a spare controller of the same model.
>
> > Or is the data lost?
>
> RAID5 is easy to recover for professionals. There is also an other
> option: dmraid (part of Linux software RAID) can assemble and use
> arrays from several different fake-RAID (software-RAID on a card,
> which is likely what you have) controllers. This may allow imaging the
> RAID under Linux, regardless of filesystem on it.
>
> My advice is to replace the controller after a full backup and
> to recreate with a new controller, of which you get two in
> order to have redundancy. Or to move to software-RAID, which does
> not have this limitation.

Or you could just make backups, eh, babblebot?

>
> Arno
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

Previously mscotgrove.RemoveThis@aol.com <mscotgrove.RemoveThis@aol.com> wrote:
> On Jan 21, 2:43 pm, Arno Wagner <m....RemoveThis@privacy.net> wrote:
>> Previously Robert Wegner <rob....RemoveThis@gmx.net> wrote:
>>
>> > Hi there,
>> > i've got an old storage server here, running W2k, with a promise
>> > pci-card raid controller. The controller hosts a raid 5 array and it
>> > is 4 or 5 years old, so i guess it isnt built any more.  So, i
>> > wonder, what if the controller fails and i can't buy exactly the
>> > same one?  Can i simply build in any new raid5-capable
>> > controller-card? Or does the controller has to be compatible in some
>> > way (to the old card)?
>>
>> The problem is that the RAID superblock is not standardized and hence
>> it it unlikely to work with a different controller, unless the
>> manufacturer specifically claims compatibility with your present
>> controller. In fact not even the place the RAID superblock is found
>> in, is standardized. That is also the reason why, when using hardware
>> RAID, you should have a spare controller of the same model.
>>
>> > Or is the data lost?
>>
>> RAID5 is easy to recover for professionals. There is also an other
>> option: dmraid (part of Linux software RAID) can assemble and use
>> arrays from several different fake-RAID (software-RAID on a card,
>> which is likely what you have) controllers. This may allow imaging the
>> RAID under Linux, regardless of filesystem on it.
>>
>> My advice is to replace the controller after a full backup and
>> to recreate with a new controller, of which you get two in
>> order to have redundancy. Or to move to software-RAID, which does
>> not have this limitation.
>>
>> Arno

> Have I got the wrong end of the stick, but Superblock is a Unix term,
> and not Windows?

Yes. As Unix did RAID long before Windows existed, it is called
a "superblock". But it is not Unix specific, it just means "the
block where geometry information and such is stored".

> I have 'struggled in the past with Unix disks as they all seem
> different relating to superblocks etc.

That would be the filesystem superblock. Similar task, but no
connection to RAID.

> The question though relates to W2K server - is Superblock relevant
> here?

Yes.

> Again, please tell me if I am wrong, but I always thought a RAID disk
> logically looked like normal big disk that just happens to be fault
> tolerant.

On the computer side, yes. But on the disk side, meta-information
needs to be stored somewere. This is done in the RAID superblock and
it will be hidden from the computer by the RAID layer.

Arno
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

Arno Wagner wrote in news:5vjpclF1mv66iU1@mid.individual.net
> Previously Robert Wegner <robweg.RemoveThis@gmx.net> wrote:
> > Hi there,
>
> > i've got an old storage server here, running W2k, with a promise
> > pci-card raid controller. The controller hosts a raid 5 array and it
> > is 4 or 5 years old, so i guess it isnt built any more. So, i wonder,
> > what if the controller fails and i can't buy exactly the same one?
> > Can i simply build in any new raid5-capable controller-card?
> > Or does the controller has to be compatible in some way (to the
> > old card)?
>
> The problem is that the RAID superblock is not standardized and
> hence it it unlikely to work with a different controller, unless the
> manufacturer specifically claims compatibility with your present
> controller. In fact not even the place the RAID superblock is found
> in, is standardized. That is also the reason why, when using hardware
> RAID, you should have a spare controller of the same model.
>
> > Or is the data lost?

> RAID5 is easy to recover for professionals.

Any RAID is, if you know how to interprete the Raid Controller metadata.

> There is also an other
> option: dmraid (part of Linux software RAID) can assemble and use
> arrays from several different fake-RAID (software-RAID on a card,
> which is likely what you have) controllers.

Like there is a huge difference on the disk side between hardware and
firmware assisted RAID but not between the firmware assisted RAIDs.

> This may allow imaging the RAID under Linux, regardless of filesystem
> on it.
>
> My advice is to replace the controller after a full backup and to recre-
> ate with a new controller, of which you get two in order to have redund-
> ancy. Or to move to software-RAID, which does not have this limitation.
>
> Arno
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

One option would be to buy a spare Promise card now, before you need it....

That said... you still need backups...


--
A host is a host from coast to coast.................wb8foz.DeleteThis@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

This message is not archived
 >> Stay informed about: What happens with a Raid 5 when the controller fails? 

Previously DonLogan <navajo.RemoveThis@neonfeather.com> wrote:
> Arno Wagner <me.RemoveThis@privacy.net> wrote:

>>Previously Robert Wegner <robweg.RemoveThis@gmx.net> wrote:
>>> Hi there,
>>
>>> i've got an old storage server here, running W2k, with a promise
>>> pci-card raid controller. The controller hosts a raid 5 array and it
>>> is 4 or 5 years old, so i guess it isnt built any more. So, i
>>> wonder, what if the controller fails and i can't buy exactly the
>>> same one? Can i simply build in any new raid5-capable
>>> controller-card? Or does the controller has to be compatible in some
>>> way (to the old card)?
>>
>>The problem is that the RAID superblock is not standardized and hence
>>it it unlikely to work with a different controller, unless the
>>manufacturer specifically claims compatibility with your present
>>controller. In fact not even the place the RAID superblock is found
>>in, is standardized. That is also the reason why, when using hardware
>>RAID, you should have a spare controller of the same model.
>>
>>> Or is the data lost?
>>
>>RAID5 is easy to recover for professionals. There is also an other
>>option: dmraid (part of Linux software RAID) can assemble and use
>>arrays from several different fake-RAID (software-RAID on a card,
>>which is likely what you have) controllers. This may allow imaging the
>>RAID under Linux, regardless of filesystem on it.
>>
>>My advice is to replace the controller after a full backup and
>>to recreate with a new controller, of which you get two in
>>order to have redundancy.

> Yes he has a working Raid & wants to migrate before failure. And he's
> waited too long.
> So how does he do this backup / replace controller / use two?
> "recreate"? Not easy. Or do Promise offer an data upgrade or
> compatibility option?

Very simple: For Backup he uses his standard backup method. If
he does not have one, the data is obvisouly worthless, and he
can just erase it. (Well, or right now establish a backup
nethod....)


>> Or to move to software-RAID, which does
>>not have this limitation.

> again - migration path?

See above.

Remember, RAID is abaout availability. It is not substitute
for backup.

Arno
 >> Stay informed about: What happens with a Raid 5 when the controller fails?