What's better? raidz2 or raidz1 with a spare configured?

[thedude]

raidz1 would be 5+1parity +1 spare (total of 7 drives)

or

raidz2 with 5+2 (total of 7 drives)

 

[matthewowen01]

depends. the raidz would be slightly faster as there is one less parity to calculate but if you loose a drive, there is a window where you have no redundancy while the data resilvers.

 

[Fornax]

Depends indeed.
With 6 + 1 drives you could also make 2 Vdevs of 3 drives and combine those in Raidz with 1 spare. That would give you a speedadvantage, similar redundancy and slightly lower usable space. So many combinations possible

 

[SilverJS]

I asked that same question when I was setting up my file server over at the FreeBSD forums, and while some suggested the 2 Vdevs in RAIDZ1, I decided not to go that way based on the advice I got over there, for two reasons :

1. Yes, two separate RAIDZ1 VDEVs can sustain two drive failures, but *only if the failures are not in the same vdev*. Which, granted, is unlikely, but there you go. (Also, the spare adds another wildcard in the equation, but with 7 drives, you'd probably have a hot spare anyways);

2. The performance advantage, from what I've gathered, would be minimal if you're using 100/1000 ethernet anyways. A 6-drive RAIDZ2 array will still saturate that connection.

So, I decided to go with a 6-drive RAIDZ2 array + hotspare (same exact situation as you, 7 drives). With a Gigabit switch, I see regular transfers at 80 Mb/sec, and sometimes even up to 100-110. I mostly depends on WHAT I'm transferring (single large files, like movie ISO's, transfer quite quickly, but the accompanying files that Media Companion generates - actors, thumbnails, etc. - are quite slower).