[OpenIndiana-discuss] ZFS read speed(iSCSI)

[Heinrich van Riel]

If only the network guys here told me this, I do have VMware with two nics
but that does not help going to the same target as pointed out. It does
load balance but the total amount is only 80-100MB/s.

So I guess I will change two of the interfaces in LACP on one VLAN and then
the other two on another on the storage server side and on VMware/Hyper-v
bind to the two different targets with no LACP

So from the all replies I will be doing the following:

   * net changes as above
   * create block volumes with blocksize 32
   * enable compression
   * add the SSD cache disk. (doing some limited testing, students will
clone from the same templates and use the same install media when, so it
seems like it would help with that by putting on the SSD, tested on system
where I could add SATA SSD)

I will post my findings, but might take some time to fix the network in
time and they will have to deal with 1Gbps for the storage. The request is
to run ~90 VMs on 8 servers connected.

Thank you all for all the responses.










On Thu, Jun 6, 2013 at 9:24 AM, Saso Kiselkov <skiselkov.ml at gmail.com>wrote:

> On 05/06/2013 23:52, Heinrich van Riel wrote:
> > Any pointers around iSCSI performance focused on read speed? Did not find
> > much.
> >
> > I have 2 x rz2 of 10x 3TB NL-SAS each in the pool. The OI server has 4
> > interfaces configured to the switch in LACP, mtu=9000. The switch (jumbo
> > enabled) shows all interfaces are active in the port channel. How can I
> can
> > verify it on the OI side? dladm shows that it is active mode
> >
> > [..snip..]
>
> Hi Heinrich,
>
> Your limitation is LACP. Even in a link bundle, no single connection can
> exceed the speed of a single physical link - this is necessary to
> maintain correct packet ordering and queuing. There's no way around this
> other than to put fatter pipes in or not use LACP at all.
>
> You should definitely have a look at iSCSI multipath. It's supported by
> VMware, COMSTAR and a host of other products. All you need to do is
> configure multiple separate subnets, put them on separate VLANs and tell
> VMware to create multiple vmkernel interfaces in separate vSwitches.
> Then you can scan your iSCSI targets over one interface, VMware will
> auto-discover all paths to it and initiate multiple connections with
> load-balancing across all available paths (with fail-over in case a path
> dies). This approach also enables you to divide your storage
> infrastructure into two fully independent SANs, so that even if one side
> of the network experiences some horrible mess (looped cables, crappy
> switch firmware, etc.), the other side will continue to function without
> a hitch.
>
> Cheers,
> --
> Saso
>
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