RAID and partitioning

[Marduk]

Hi,

I would like to know if it is possible to have a single disk partitioned and use these partitions as mirrors (RAID 1).

Maybe the question would be: can you use RAID 1 on a single disk? Then the second question would be: do you need to partition first or is this taken care off when configuring RAID 1?

(subquestion: how does this affect the recovery part that was made when installing the OS?)

Thanks

[acme.mail.order]

1) No.

2) not applicable.

RAID is meant for either performance enhancement (striped) or data redundancy (mirror). Putting 2 parts of a RAID set on one physical device defeats both goals, with the added bonus of a major performance reduction if you did manage to force it to do a mirror on the same device. Think about the mechanics - the heads would have to write a sector's worth of data, then move all the way over to the other partition and repeat the process.

[agentx]

You cannot have a recovery partition a RAID set.
But you can always create a USB recovery drive on an 8GB USB flash drive if you want to run RAID and have ability to boot computer from it

[DeltaMac]

For a RAID 5 set, which includes a minimum of 3 drives, the rough capacity of the RAID 5 set is the sum of the individual drives, minus the space of one of the drives.
So, if you have a RAID 5 set consisting of 5 250GB drives, your approximate storage space would be (250 x 5) - 250 = 1,000 MB (1 GB, more or less)
There's lots of information about the various RAID levels, just search for that. Here's a quick page with the information about computing storage space on a RAID-5 set. http://www.ehow.com/how_7504586_calc...ge-raid-5.html

Can you use your existing drive? probably OK, although I would suggest that you purchase a set of identical new drives to use in your RAID, so you have some idea about the health of all the drives before you start...

[Marduk]

Thanks Acme.mail.order. I was trying to get confirmation. The mechanics were exactly my worries. So thanks for confirming my thoughts.

[anthlover]

You did not say why you wanted RAID. Note: Raid is not a substitute for a back up. Back ups should come as a first in priority. RAID is short for Redundant array of Inexpensive/Independent Disks.

Though I provide a link below with more info. RAID has two purpose to prevent a catastrophic failure of a single disk from losing what is on it or to speed up access to Data. Note that a Single SSD can achieve the speed of many arrays without breaking a sweat but of course the current price hovering around $1 GB current common large size is 512GB though there are some in the 784 and 1TB size. Your currently generally better of combining two.

Very few individuals require raid because their data does not change so often. Business on the hand has data that changes moment by moment which is where raid is an absolute requirement.

I put a link below for a RAID Calculator and Explanation of RAID types which also has explanations of strengths and weakness below.

http://www.icc-usa.com/raid-calculator.php

Perhaps you can tell us what you want to achieve with RAID and a little about your current system. Note that back ups too should involve multiple separate Physical disks and ideally also an off site back up using something like crash plan.

The simplest and least expensive RAID for speed or redundancy is a two drive set up. Raid 0 and and RAID 1. The former only achieves speed and the latter only redundancy.