FreeBSD 8.1-R/amd64 - zfs 'hangs' - help tracing?

[Jeremy Chadwick]

On Wed, Sep 29, 2010 at 10:20:22AM +0100, Karl Pielorz wrote:
> 
> Hi All,
> 
> I moved my machine from FreeBSD 7.2-S/amd64 to 8.1-R/amd64 about a
> week ago. Since then I've noticed that ZFS just 'hangs' - e.g. it'll
> work fine for a few days, then a process will get 'hung up' waiting
> on ZFS.
> 
> The machine is a Tyan motherboard (dual Opteron, dual cores, w/10Gb
> of RAM). 7.2-S & ZFS ran perfectly under it.
> 
> Anything else then that touches the pools, also 'hangs' - in top the
> original process shows as:
> 
> "
> 1927 root        1  44    0  8224K  1544K zio->i  0   0:00  0.00% ls
> "
> 
> Anything else that touches the ZFS pools, ends up like:
> 
> "
> 2082 root        1  44    0 10284K  2976K zfs     3   0:00  0.00% csh
> "
> 
> I saw a while ago a command under 8.1 to get 'more info' for these
> stuck processes, but can't for the life of me remember it?
> 
> If someone can give me some pointers to try and track down what's hanging?
> 
> The drives are spread over two Marvell 88SX6081's. I've tried the
> mvs driver for that controller, which gave me a bucket load of
> errors, and data corruption :(
> 
> Switching back to the standard ATA drivers for that card, I just get
> hangs :( - nothing is logged on the console, or syslog when this
> happens.

Can you provide (with the disks hooked to an ATA/SATA controller and
the system not wedged waiting for ZFS I/O) the output from smartctl
(you'll probably have to install ports/sysutils/smartmontools) as:

smartctl -a /dev/adXX (one command per device)

I can review these statistics to see if any of the disks look like they
may be misbehaving.

It would also help if you could provide dmesg output associated with the
ATA/SATA controller which they're hooked to.

Thanks!

-- 
| Jeremy Chadwick                                   jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |