angelus249
Dabbler
- Joined
- Dec 19, 2014
- Messages
- 41
Hello together,
just a few details to explain what I'm up to.
I'm currently running a small setup with 3+1 4TB disks in RAIDZ1. Since it was an initial test 2 years ago, I built it small and cheap and therefore can't expand now. I will change that tho so I can expand up to 22 disks.
The new system will have an additional 4TB drive and I will make a 4+1 RAIDZ1 vdev (a new one, I know I can't expand the old one) as well as a mirrored SSD volume for jails/plugins/.system. I will also add another 5x8TB, likewise in RAIDZ1. After that I'll have space for 10 more drives.
I'm aware of all the differences in RAIDZ1/Z2, buying from different badges, vendors etc., but in terms of future growth I've come to a design question I can't find a satisfying answer to.
Hence my question:
Would you rather add twice 4+1 disks in RAIDZ1 or straight a big pool of 8+2 as RAIDZ2. The total amount of redundancy disks for both setups is the same. The pro's for 2x RAIDZ1 would be I don't have to buy 10 disks at the same time. But Con's?
Since the total amount of 10 disks remains the same in both cases, any of them could fail. But without putting my math cap on I'd think from a statistical point of view it's probably safer to run a big 8+2 RAIDZ2, since any two drives could fail here and the vdev would still work. If two random drives would happen to fail in one of the RAIDZ1 pools, I'd be f*cked. If we go as far as assuming 3 drives would fail more or less simultaniously, I'd be doomed either way. But in the RAIDZ1 scenario I would at least lose only half of my data, while the 2nd pool would be still alive. I guess it's a tradeoff. But assuming Murphy wouldn't destroy 3 drives at the same time, a RAIDZ2 is probably the better choice.
I'd appreciate some input.
Cheers
just a few details to explain what I'm up to.
I'm currently running a small setup with 3+1 4TB disks in RAIDZ1. Since it was an initial test 2 years ago, I built it small and cheap and therefore can't expand now. I will change that tho so I can expand up to 22 disks.
The new system will have an additional 4TB drive and I will make a 4+1 RAIDZ1 vdev (a new one, I know I can't expand the old one) as well as a mirrored SSD volume for jails/plugins/.system. I will also add another 5x8TB, likewise in RAIDZ1. After that I'll have space for 10 more drives.
I'm aware of all the differences in RAIDZ1/Z2, buying from different badges, vendors etc., but in terms of future growth I've come to a design question I can't find a satisfying answer to.
Hence my question:
Would you rather add twice 4+1 disks in RAIDZ1 or straight a big pool of 8+2 as RAIDZ2. The total amount of redundancy disks for both setups is the same. The pro's for 2x RAIDZ1 would be I don't have to buy 10 disks at the same time. But Con's?
Since the total amount of 10 disks remains the same in both cases, any of them could fail. But without putting my math cap on I'd think from a statistical point of view it's probably safer to run a big 8+2 RAIDZ2, since any two drives could fail here and the vdev would still work. If two random drives would happen to fail in one of the RAIDZ1 pools, I'd be f*cked. If we go as far as assuming 3 drives would fail more or less simultaniously, I'd be doomed either way. But in the RAIDZ1 scenario I would at least lose only half of my data, while the 2nd pool would be still alive. I guess it's a tradeoff. But assuming Murphy wouldn't destroy 3 drives at the same time, a RAIDZ2 is probably the better choice.
I'd appreciate some input.
Cheers