Some ZFS experience

[Wojciech Puchar]

>
> What happened:
> 1. Base system running on gmirror volume consisting of 4 mirrors booted
> up normally in degraded mode with 3 of 4 drives online.
> 2. /data powered by raidz1 zfs was showing 3 drives, 2 online and 1
> faulted. zfs list was showing that volume is unavailable due lack of
> spares.

you told about having raidz over 4 drives.
so while it reports 2 online and 1 faulted, not 3 online and 1 faulted?

> What was wrong when 3 drives were connected? Wasnt supposed to raidz1
> survive lack of 1 drive? Or I did something wrong there?

yes it should work normally. in case of raid-z - with just a bit slower 
speed according to ZFS theory.