iscsi-target monitoring

[Jimmy]

I've been playing around with iscsi-target, creating and connecting to a LUN from a windows 7 initiator to my FreeBSD box.

The FreeBSD box is a C7 1.5GHZ with 1GBE Realtek interface. 1GBE on the initiator too. I'm really impressed with the performance, I'm using bit locker to encrypt the volume too and it's lightning fast across the network.

I was getting 'No buffer space available' the first time I attempted formatting but it seems to have worked after tweaking the MTUs on Win7 machine and enabling Jumbo frames, although I do occassionally see connectivity stutter but this appears to resolve itself. Auto tuning in FreeBSD 9 means I shouldn't have to adjust TCP settings. Although when I got the buffer error the box had to be restarted as it wouldn't recover even with flapping the interface.

Cutting to the chase, there's not a lot of documentation on iscsi-target, does anyone know how I can monitor the IOPS or network traffic specifically to the LUN from the FreeBSD box?

I understand FreeBSD will inherently not be aware of the LUN activity, but the iscsi-target software should be?

 

[Jimmy]

So I'm reading about ZFS and it looks like it may be possible to create an iSCSI target / LUN using zpools, again there's scant information out there and both the FreeBSD Wiki and handbook seem to have outdated information, for example:

Handbook:
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/filesystems-zfs.html
States to set the following:

vm.kmem_size="330M"
vm.kmem_size_max="330M"
vfs.zfs.arc_max="40M"
vfs.zfs.vdev.cache.size="5M"

But in 9.0 Release my default Max sizes exceed these values:

[root@diesel /etc]# sysctl vm.kmem_size_max
vm.kmem_size_max: 429916160
[root@diesel /etc]# sysctl vfs.zfs.arc_max
vfs.zfs.arc_max: 93094400

Regarding the Wiki I found this:
http://wiki.freebsd.org/ZFS

There is no iSCSI target daemon in FreeBSD currently that's why 'zfs set shareiscsi' is not supported"

But this appears to be available in the zfs manual and the command zfs set shareiscsi works.

Is there any documentation on this and how to create and share LUNs?

 

[Jimmy]

Although the [CMD=]zfs set shareiscsi[/CMD] command returns when you attempt to apply this to a zpool it returns invalid property, so it doesn't appear to be functional.

It seems like you can use net/istgt from the ports with zfs pools. Or if you just want a straightforward LUN on a disk, net/iscsi-target from the ports seems to work very well.

 

[Pantagruel]

If you want ZFS and iSCSI support you should try ZFSguru. It's FreeBSD based, easy to install and maintain. Eventhough it's quite a 'young' distro, the ZFSguru dev's and community are quite active regarding maintaince, providing help and feature requests.