Raid 5 questions

[Jump4h]

I have a Gigabyte UD-7 which supports Raid 0,1,5 and 10. I currently have one 2TB drive which contains all my essential, REALLY important info.

I recently bought three identical 2TB drives. I intend to do raid 5 after reading this guide. First and foremost I want minimal overhead but also security.

 

Now, on to the questions.

 

1.When creating the Raid Array, am I to transfer all data from my existing hard drive to external ones first and then create the array of four disks, or can I simply add it to the three brand new disks?

2.Is raid 5 the best option for me?

3. I've read the manual on how to create the array. It states that I need a floppy drive. Can a USB drive be used instead, because I haven't had a floppy drive in years.

[ir_cow]

you need a minimal of 3 drives to start a raid 5. i believe you need to back your stuff up somewhere else because it will wipe those drives clean to setup the strips. i do know when it comes to LSI cards you can create raids with data on it already but thats risky in any case.

 

As for best option it depends on what you are doing with the raid. because raid 5 can only support 1 failure at a time but gives speeds that of raid-0. now raid 1 is just a straight mirror of the first drive with double the overhead since everything has to be written twice. If you are just doing it for file storage raid1 might be the best since you only need 2 drives and it's cheaper. past that raid 5 is good for quick data like movie rendering and or storage. if you move past that you are starting to look into large scale sever options that is costly.

Edited July 15, 2011 by hornybluecow

[Nemo]

Yes, you will need to back up the data on the existing drive before creating the RAID volume as it will destroy on the all the drives as it builds the array.

 

Next, you will not see RAID 0 speeds from a software RAID 5 setup because of the XOR calculations needed for the parity information. How much slower depends on your setup - it's not going to break the bank if you're using it just for storage. You can check out some of the OCC reviews of NAS units to get an idea of comparative performance.

 

The next question is to ask why you're going to RAID? Is it for security - as mentioned above, a RAID 5 array can survive the loss of a single drive while still making your data available, although in a degraded (slower) mode. It will not protect you against data loss from other reasons like a corrupted volume, fire, theft etc. It is not a substitute for a good backup policy. Let me repeat that - don't use a RAID volume in lieu of a good backup plan.

 

IMO, RAID 5 gives you the best tradeoff between performance and security while sacrificing the least amount of disk space.