From: Tony Williams 

Geo. wrote:
> Mirroring is writing the same data to two drives, it's good for data
> redundancy where uptime is important because if the main drive fails you can
> switch the two drives around and boot from the mirror.

Yup, that's why I mentioned in the context of guarding against data loss
due to a failing hard drive.

Thanks for stepping in with a good explanation - it looks like I overstated
the capabilities of RAID 1.

--
Tony

> RAID5 is writing data to a series of at least 3 drives, two would be the
> actual data and the third would be a checksum of the two. This way if a
> drive fails  you can rebuild the data that was on it from the other two. If
> you use 5 drives then 4 are data and one checksum, etc.
>
> Raid0 is striping, this is where data is written to 2 or more drives with no
> checksum. It increases the speed of reading and writing to disk but lose one
> drive and it's all gone.
>
> None of these serves the same purpose as a backup though. With any of these
> setups if you delete something by accident, it's gone and you have no way to
> get it back. With a backup you would just restore it.
>
> Geo.
>
> "Tony Williams"  wrote in message
> news:3DC4E7BB.7020701{at}blarg.net...
>
>>There are a few different RAID configurations; RAID 1 is disk mirroring,
>>others deal with striping.
>>
>>I'm no expert but as I understand it when you mirror two drives they
>>both get all the information at the same time.
>>
>>The OS and system files get stored on both drives and the system will
>>read from whichever drive can provde the data - down to the extent of
>>reading half a file from one drive and the rest from the other.
>>
>>Hey, Geo! You know more about this than me - any advice?
>>
>>--
>>Tony
>>
>>Ellen K. wrote:
>>
>>>?   Aren't mirroring and RAID two different things?   I thought RAID
>>>stripes the data on different disks so if one fails the system can
>>>figure out what got lost, and mirroring is just what it sounds like...
>>>
>>>So a mirroring question, does the mirror read from the bad drive or does
>>>everything write originally to both?
>>>
>>>Finally, if the problem is on the part of the C drive that has the O/S
>>>and/or program files, what is the result with RAID and with mirroring?
>>>
>>>On Sat, 02 Nov 2002 21:31:40 -0800, Tony Williams 
>>>wrote in message :
>>>
>>>
>>>
>>>>Ellen,
>>>>
>>>>If you're serious about using an extra drive to improve
data integrity
>>>>you might want to look into RAID mirroring. The various
Windows Server
>>>>editions support it in software so all you need to buy is the extra
>>>
> drive.
>
>>>>Here's a page with a good explanation and links to HOWTOs :
>>>>
>>>
>>>http://www.microsoft.com/windows2000/en/server/help/default.asp?url=/WINDO
>>
> WS2000/en/server/help/sag_FAULTconcepts_01.htm
>
>>>>A search for "mirrored volumes" at MS's web site
pulls up several useful
>>>>links.
>>>
>>>
>>
>
>

--- BBBS/NT v4.01 Flag-4