Berdine
Cadet
- Joined
- May 11, 2015
- Messages
- 8
Hi,
Having read the excellent guide written by Cyberjock about ZFS storage design and other FreeNAS information, some points about zpools are not totally clear to me. I would be very thankfull if you can enlighten me.
In an example in the guide (example 2), we have one zpool containing 2 vdev in RAID-Z2, each one made of 6 hard disk.
"This zpool provides redundancy against a maximum of 4 simultaneous hard disk failures(2 in each VDev), but not 3 in any one VDev." As I understand it, if 3 disks in any one vdev crash, the entire zpool is crashed : no data can be restored.
In all the examples of this guide, there is only one zpool. Can we have more than one zpool ? I do hope so, and as I understand it, we can.
So, is there any interest in this configuration, instead of having two zpools, each containing 1 vdev in RAID-Z2, each one of these vdev made of 6 hard disk?
The result would be the same ("These zpools provide redundancy against a maximum of 4 simultaneous hard disk failures(2 in each VDev), but not 3 in any one VDev."), but if 3 disks fail in any one vdev, the other zpool would not be crashed.
I clearly understand that it is only an example, but I am troubled by the fact that not any one example mention two zpools.
If I lack some understanding on this, I am afraid to make mistakes building my own NAS.
Indeed, I would like to have the following configuration :
- one zpool P1 containing one vdev V1 of 2 hard disks D1 and D2 in mirror mode, containing data.
- one zpool P2 containing one vdev V2 of 1 hard disk D3 in stripe mode, containing music and movies, for access for everyone at home, but with no need of redundancy.
- one zpool P3 containing one vdev V3 of 1 hard disk D4 in stripe mode, for storage for peer-to-peer, using transmission; no need of redundancy either.
This way, my data are reasonably safe, my medias always available, and my data server working, all in one.
In the future, I shall add another hard-disk D5 in the vdev V2 to make a mirror, if I want redundancy, but that is not my priority. I shall also add a spare hard disk, but for now, if any of the hard disk in V1 crash, I will replace it by D4.
Do you have any suggestion, or advice on some point I would have missed ?
Thank you by advance. And excuse me for my english, hope I have been clear.
Having read the excellent guide written by Cyberjock about ZFS storage design and other FreeNAS information, some points about zpools are not totally clear to me. I would be very thankfull if you can enlighten me.
In an example in the guide (example 2), we have one zpool containing 2 vdev in RAID-Z2, each one made of 6 hard disk.
"This zpool provides redundancy against a maximum of 4 simultaneous hard disk failures(2 in each VDev), but not 3 in any one VDev." As I understand it, if 3 disks in any one vdev crash, the entire zpool is crashed : no data can be restored.
In all the examples of this guide, there is only one zpool. Can we have more than one zpool ? I do hope so, and as I understand it, we can.
So, is there any interest in this configuration, instead of having two zpools, each containing 1 vdev in RAID-Z2, each one of these vdev made of 6 hard disk?
The result would be the same ("These zpools provide redundancy against a maximum of 4 simultaneous hard disk failures(2 in each VDev), but not 3 in any one VDev."), but if 3 disks fail in any one vdev, the other zpool would not be crashed.
I clearly understand that it is only an example, but I am troubled by the fact that not any one example mention two zpools.
If I lack some understanding on this, I am afraid to make mistakes building my own NAS.
Indeed, I would like to have the following configuration :
- one zpool P1 containing one vdev V1 of 2 hard disks D1 and D2 in mirror mode, containing data.
- one zpool P2 containing one vdev V2 of 1 hard disk D3 in stripe mode, containing music and movies, for access for everyone at home, but with no need of redundancy.
- one zpool P3 containing one vdev V3 of 1 hard disk D4 in stripe mode, for storage for peer-to-peer, using transmission; no need of redundancy either.
This way, my data are reasonably safe, my medias always available, and my data server working, all in one.
In the future, I shall add another hard-disk D5 in the vdev V2 to make a mirror, if I want redundancy, but that is not my priority. I shall also add a spare hard disk, but for now, if any of the hard disk in V1 crash, I will replace it by D4.
Do you have any suggestion, or advice on some point I would have missed ?
Thank you by advance. And excuse me for my english, hope I have been clear.