Re: RAID 1 versus RAID 5

From: Fred Blum (h.f.blum_at_marketconnectnospam.nl)
Date: 12/02/04 

Date: Thu, 2 Dec 2004 09:25:45 +0100

Thanks,

had not thought of that and you're right. My RIAD controller doesn't allow a
dynamic resizing on W2K.
IMHO opinion this thread question/answer should be in the FAQ.

Fred

"Joshua Bolton" <JoshuaBolton@discussions.microsoft.com> wrote in message
news:5AC99C16-73A5-4B52-98B6-113D9E26E73D@microsoft.com...
> Kevin I would point out that this configuration precludes any disk space
> being added to your system. This is why the standard has been mirror
> [raid1]
> the OS and stripe [raid 5/0+1/10] the data.
>
> Here is the reason why. It is common to need to add disk space to the
> data
> partition/drive. Most raid controllers don't allow dynamic upgrades in
> the
> raid array. So to add more disk space with your present configuration you
> have to wipe the existing array and recreate the raid5 array with the
> additional disk so you have more space. This usually means you have to
> repartition the way you want, reinstall the OS and backup software and
> restore from a backup. A long painful process.
>
> Lets say you have a raid controller that can add the disk to the array
> dynamicly. Great. Now you have system, apps and data partitions. How
> are
> you going to add the "unallocated space" to the data partition? You only
> have two options. The best being buy a server version of Partition Magic
> and
> use it to add the space to data. Or create a volume set between the data
> partition and the unallocated space [very bad choice since I have seen
> chkdsk
> /f destroy a volume set].
>
> Now if you had mirrored the OS and stripped the data [in your case apps
> and
> data] it is a simple matter of backup apps and data, reinit the array with
> the added disk, use disk manager to partition as you desire and format the
> partitions. Then restore from backup. I have done this in 4 hours on a
> Sat.
> [depending on how long it took to init the array and restore data].
>
> Lets say you wanted to make the OS drive space larger. You can't mirror
> to
> a larger drive. But you can break the mirror, use ghost to ghost from
> small
> driver to larger and then with another larger drive in the system mirror
> the
> two. Again a fairly straight forward operation which you can not do if
> you
> have all three partitions on a single raid5 array. This is a two hour or
> less operation.
>
> Just something to think about.
>
>
>
> "Kevin Weilbacher" wrote:
>
>> Fred, I know way back when it was recommended not to use raid-5 for your
>> system partition. But I don't believe that is applicable any longer. I
>> know
>> I use hardware Raid-5 for all my SBS servers without any problems. I take
>> my
>> 3 or 4 drives, set them up in Raid-5, and partition them into 3 sections:
>> system, apps, data.
>

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