ZFS reports problem on iscsi target

[Daniel Braniss]

> Hi,
> 
> I'm having some trouble with iscsi on FreeBSD 8. My current setup is a
> stock FreeBSD 8.1-PRERELEASE (as of 2 days ago), GENERIC kernel with
> some modules loaded, running on a Dell PowerEdge R905 with 64GB RAM, 4
> quad code CPUs. Attached is an EqualLogic PS6500 storage array with some
> configured volumes, one of which is for testing. It is configured in
> /etc/iscsi.conf like this:
> 
> test2 {
> 
> TargetName=iqn.2001-05.com.equallogic:0-8a0906-7a4bb9f06-038000000304c0d1-test2
>   TargetAddress=10.26.17.10:3260,1
>   tags = 256
> }
> 
> Now I'm running the following sequence of commands (shown with output):
> 
> # iscontrol -n test2
> iscontrol[56255]: running
> iscontrol[56255]: (pass2:iscsi0:0:0:0):  tagged openings now 256
> iscontrol[56255]: cam_open_btl: no passthrough device found at 2:0:1
> iscontrol[56255]: cam_open_btl: no passthrough device found at 2:0:2
> iscontrol[56255]: cam_open_btl: no passthrough device found at 2:0:3
> iscontrol: supervise starting main loop
> # zpool create test2 da2
> # zpool scrub test2
> # zpool status test2
>   pool: test2
>  state: ONLINE
>  scrub: scrub completed after 0h0m with 0 errors on Fri Jun 11 16:56:33 2010
> config:
> 
>         NAME        STATE     READ WRITE CKSUM
>         test2       ONLINE       0     0     0
>           da2       ONLINE       0     0     0
> 
> errors: No known data errors
> # cp -Rp /export/system /test2/
> # zpool scrub test2
> # zpool status test2
>   pool: test2
>  state: ONLINE
> status: One or more devices has experienced an error resulting in data
>         corruption.  Applications may be affected.
> action: Restore the file in question if possible.  Otherwise restore the
>         entire pool from backup.
>    see: http://www.sun.com/msg/ZFS-8000-8A
>  scrub: scrub completed after 0h0m with 19 errors on Fri Jun 11 17:00:38
> 2010
> config:
> 
>         NAME        STATE     READ WRITE CKSUM
>         test2       ONLINE       0     0    19
>           da2       ONLINE       0     0    38
> 
> errors: 19 data errors, use '-v' for a list
> #
> 
> /export/system is a FreeBSD distribution (make install
> DESTDIR=/export/system). Note how zfs thinks there are 19 files broken
> after the copy. If I repeat the process, the files vary, but there are
> always some reported as broken. In this case, they don't seem to be (as
> checked with md5 and rsync --checksum), but I've had files only giving
> me an i/o error. Also, if I repeat the same steps on a local disk, zfs
> is reporting no errors.
> 
> What I would like to know is:
> - Is there anything I'm doing wrong? Is there a known problem?
> - Are there any tools to debug or more reliably reproduce (and narrow
> down) the problem? I've tried fsx (from /usr/src/tools/regression), but
> I couldn't find any usage suggestions (other than the usage when run
> without options) and it doesn't complain when run.
> - On a different system I've tried using a newer iscsi version from
> http://www.cs.huji.ac.il/~danny/ftp/freebsd/ but it didn't make any
> difference. Is that still preferable?
> 
> Some help would be appreciated.

Hi Rolf,
	I just ran a bunch of tests, like yours, without any problem.
my setup:
the target is a NetApp, the host runing the initiator is an
 AMD Phenom(tm) II X6 1090T Processor, running a very resent 8.1-PRERELEASE
with 4GB of RAM so that  "vfs.zfs.prefetch_disable" is true, so maybe
you can try disabling it?
appart from that, maybe you can check EqualLogic's logs.
HTH,
	danny
PS: you should use the latest iscsi-2.2.4.tar.gz