Questions about RAID and FreeNAS

[ellupu]

Heyho,
first of all, I'm completely new to freeNAS and never had experience with servers based on Linux (or Unix? - first fail *ouch*)

Okay, so my second fail was to decide myself to buy non-ECC RAM, while I was nearly a heartattack, when I read some threads about lost zpools and that discussion between non-ECC and ECC RAM from cyberjock. So okay, I'm gonna get myself asap to the next shop buying some ECC RAM.

I took myself also time to read the official freenas guide (still not finished) looking for a solution for my setup. Currently I own 2x3TB WD Red HDD which I would like to use in a RAID0 setup (I'm aware of the risk losing data, that's why I have a backup NAS) and later I would like to extend my space with another 3x3TB HDD using a RAID5.

1. I'm not sure if this is possible switching from RAID0 to 5 without loosing the data. As far as I understood (english isn't my native language) there is no possibility to stripe an existing volume / RAID?
2. What solution would be the best for my scenario?
3. Is it correct that RAIDz1 = RAID5, while "z" stands for the number of spare drives? (simplified)

Thanks in advance for your help!

 

[Neil Whitworth]

1. I'm not sure if this is possible switching from RAID0 to 5 without loosing the data. As far as I understood (english isn't my native language) there is no possibility to stripe an existing volume / RAID?
2. What solution would be the best for my scenario?
3. Is it correct that RAIDz1 = RAID5, while "z" stands for the number of spare drives? (simplified)

1. No - You need to destroy and re-create your pool to do this. see Cyberjock's guide for details
2. That depends - How much risk are you willing to take? Note that raid5/raidz1 are considered risky. A 6 drive RaidZ2 pool is popular round here.http://www.zdnet.com/blog/storage/why-raid-5-stops-working-in-2009/162
3. Yes - Raidz1's closest equivilant is raid5. They both use a single drives worth of parity, and can continue with one failed drive. Raid6/RaidZ2 use 2 drives worth of parity to provide additonal redundany.

 

[Shroom]

Heyho,
first of all, I'm completely new to freeNAS and never had experience with servers based on Linux (or Unix? - first fail *ouch*)

Okay, so my second fail was to decide myself to buy non-ECC RAM, while I was nearly a heartattack, when I read some threads about lost zpools and that discussion between non-ECC and ECC RAM from cyberjock. So okay, I'm gonna get myself asap to the next shop buying some ECC RAM.

I took myself also time to read the official freenas guide (still not finished) looking for a solution for my setup. Currently I own 2x3TB WD Red HDD which I would like to use in a RAID0 setup (I'm aware of the risk losing data, that's why I have a backup NAS) and later I would like to extend my space with another 3x3TB HDD using a RAID5.

1. I'm not sure if this is possible switching from RAID0 to 5 without loosing the data. As far as I understood (english isn't my native language) there is no possibility to stripe an existing volume / RAID?
2. What solution would be the best for my scenario?
3. Is it correct that RAIDz1 = RAID5, while "z" stands for the number of spare drives? (simplified)

Thanks in advance for your help!

Do you really need 6TB of RAID 0? Why not get a couple 1TB Blacks in RAID 0 and supplement it with the NAS. You'd get better performance out of the RAID0 with Black drives.

This'll also save you a couple bucks which you can put towards a FreeNAS build. As Whiteworth said, 6 is a good number. RaidZ2 is what you want.