Hi all, a quick question from a newbie.

 

I have a new HP Microserver and 2x2tb drives arriving this week. My orginal thought was to have these in a raid 1 array. However i've read a lot since about having a parity drive.

 

My question is should I have a single 2tb data drive and a 2tb parity drive? Where do i stand if the data disk fails?

dr-

 

I am not much above a newbie, but will offer what I (think) know. 

 

Using unraid, you will not be configuring a hardware raid array (like you talk about).  You do not setup hardware mirroring.

 

Instead, using unraid, you either have an array with a parity drive (so one of your drives is parity) and a data drive, or you would setup the array with no parity.

 

I obviously don't recommend no parity as then you have no protection against loss of data.

 

If you are going to use unraid, then if I were you I would, in addition to those 2 drives, buy a 3 TB drive to setup as my parity drive.  Then, you could add your 2 2tb drives as data drives to your array.

 

 

Many thanks for your reply. Moving forward i will probably get a third drive, however. At the moment if my data drive were to fail would i be able to retireve my data to a new drive using the parity drive??

As long as you have a parity drive, and parity is valid, then when you replace your bad data drive, unraid should be able to rebuild your data, yes.

 

This has happened to me.  I have 3 drives:

 

2 TB  Parity

1.5 TB Data

2.0 TB Data

 

My 2 TB data drive died.  My array stayed up and was accessible.  I swapped out the bad drive for a new tested and precleared drive and over the next several hours, unraid rebuilt the data on this drive.  Worked like a champ. 

 

Now, what I have now is a spare 2 TB drive that has been precleared (search the wiki for preclear) and is ready to go if/when I lose another drive.  There are positives and negatives to this.

 

Positive is if I lose a data drive, I am only without data protection for as long as it takes me to swap out the drive and have the data rebuilt.

 

The negative is I have a 2 TB drive just sitting there and I am not filling it with data goodness!

 

Hope this helps.

Many thanks for your reply. Moving forward i will probably get a third drive, however. At the moment if my data drive were to fail would i be able to retireve my data to a new drive using the parity drive??

 

Yes, you need the parity drive in order to reconstruct the data, in case of a drive loss. Parity drive has to be at least as big as the largest drive in the array. Of course, with only two drives, there is a lot of "waste"... parity takes half of your total drive capacity.  The data/parity ratio of course improves as you add more drives, and they can be drives of different sizes.

Many thanks guys.

 

Glad to know my data will be safe with just the two drives. 

 

HP Microserver arrives tomorrow, then the configuration begins!!