This is the same configuration we use on 4 separate servers (T2000, two
X4100, and a V215). We do use a different iSCSI solution, but we have
the same multi path config setup with scsi_vhci. Dual GigE switches on
separate NICs both server and iSCSI node side. We suffered from the
e1000g interface flapping bug, on two of these systems, and one time a
SAN interface went down to stay (until reboot). The vhci multi path
performed flawlessly. I scrubbed the pools (one of them is 10TB) and no
errors were found, even though we had heavy IO at the time of the NIC
failure. I think this configuration is a good one.
Jon
Gary Mills wrote:
> I'm testing an Iscsi multipath configuration on a T2000 with two disk
> devices provided by a Netapp filer. Both the T2000 and the Netapp
> have two ethernet interfaces for Iscsi, going to separate switches on
> separate private networks. The scsi_vhci devices look like this in
> `format':
>
> 1. c4t60A98000433469764E4A413571444B63d0 <NETAPP-LUN-0.2-50.00GB>
> /scsi_vhci/[EMAIL PROTECTED]
> 2. c4t60A98000433469764E4A41357149432Fd0 <NETAPP-LUN-0.2-50.00GB>
> /scsi_vhci/[EMAIL PROTECTED]
>
> These are concatenated in the ZFS pool. There are two network paths
> to each of the two devices, managed by the scsi_vhci driver. The pool
> looks like this:
>
> # zpool status
> pool: space
> state: ONLINE
> scrub: none requested
> config:
>
> NAME STATE READ WRITE CKSUM
> space ONLINE 0 0 0
> c4t60A98000433469764E4A413571444B63d0 ONLINE 0 0 0
> c4t60A98000433469764E4A41357149432Fd0 ONLINE 0 0 0
>
> errors: No known data errors
>
> The /kernel/drv/scsi_vhci.conf file, unchanged from the defaut, specifies:
>
> load-balance="round-robin";
>
> Indeed, when I generate I/O on a ZFS filesystem, I see TCP traffic with
> `snoop' on both of the Iscsi ethernet interfaces. It certainly appears
> to be doing round-robin. The I/O are going to the same disk devices,
> of course, but by two different paths. Is this a correct configuration
> for ZFS? I assume it's safe, but I thought I should check.
>
>
--
- _____/ _____/ / - Jonathan Loran - -
- / / / IT Manager -
- _____ / _____ / / Space Sciences Laboratory, UC Berkeley
- / / / (510) 643-5146 [EMAIL PROTECTED]
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