zpool degraded - 'UNAVAIL cannot open' functioning drive

[Matt Simerson]

On Aug 7, 2008, at 12:28 AM, Randy Bush wrote:

>> 1) Are you trying to tell me that individuals running commercial
>> services in production environments should run CURRENT?  I don't
>> think many are willing to do this; I know I'm not, and I can probably
>> speak for Randy Bush.  ;-)
>
> depends on what you say. :)
>
> i am personally (not day job) running current with zfs on one  
> production
> server and contemplating more[0].  i am running current ufs on a  
> number of
> other servers.
> <snip>
> ---
>
> [0] need to build a 20tb raidz2 system, kind of an nfs store to serve
> some data collertor(s) and compute egine(s).  trying to sort out disk
> controller and 10ge card decisions and the hardware / freebsd support
> space is complex.

SuperMicro 24 disk chassis (CSE-846TQ-R900B)
24 1TB SATA disks
(2) Areca 1231ML controllers with BBWC

Two RAID 5 partitions with no hot-spare disks will net you 19TB of  
formatted storage. If you ZFS stripe across the two RAID arrays,  
you'll get decent performance. If your data is compressible, enabling  
file system compression will easily store the 20TB you need.

If you have heavy I/O load, do not use raidz2 in 7.0 lest you  
experience the instability and hangs that many of us are seeing. Use  
8.0-HEAD with the latest patches and with a little luck, you'll have  
lots of storage and stability.

Matt