Mirrorview constraints

Why not fiber ? I've used fiber up to 63 kilometers without any serious problems.
But if you can't get fiber, you need to implement iSCSI over copper or FCIP over copper.
I think the minimum required speed is 64kbps (might be 128, I'm not sure).

But what you need to consider is the response times. If you're using MV/A this isn't an issue since the host won't notice anything from the delays, except that the Clariion will use up more memory. When using MV/S the response times are very important and when your bandwidth is very tiny, the hosts will notice this for each and every I/O.

You need to find out the sweet spot yourself: what's acceptable and don't cost too much..... It all depends on the persons who will notice the delays. As soon as they start complaining, start running

You also might want to review the Mirrorview White paper:

White Paper: MirrorView Knowledgebook: FLARE 28 - A Detailed Review

http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/H2417_clariion_mirrorview_asynch_dr_wp_ldv.pdf


glen

Hi,

I'm having trouble find any papers that can verify my query.

I have a 1000MB iSCSI link to a DR site 5km away can i use Mirrorview/S, would this be a sufficient link?

I've been said that mirrorview/s needs at least 1Gb fiber connection to
work properly.

Consty

Mirrorview needs at least 64 or 128kbps (ISDN speed indeed).
It depends on you application if you need faster links. I your priority lies with people who will complain when an application is slow, and this app writes a lot to replicated disks, you might want low latency links between the sites, but once again: it all depends on your own priority's.

Thanks for the answer, was helpful.

Another question is:
I have Mirrorview/A working with a site 5Km away. A new link was installed so we can now use Mirrorview/S.

The Primary CX3 is showing MV/A and MV/S software is installed but the secondary CX3 is only showing MV/A installed.

Does MV/S need to be on both Primary and Secondary Arrays for it to work?

Software was installed by EMC.

Yes. All software that you would like to use, needs to be enabled on every machine you want to use it on.

Hi,

You have to verify the MV/S license on secondary have or not by checking with EMC or EMC parner who sold the box.

If the license had purchased tell them to enabler it on secondary box.

Hope this help.

Ok, but what about latency ? A manager 1Gbps tunnel had probably a higher latency than a dark fiber which you can control yourself (without additional equipment somewhere inbetween). Throughput is 1 end of the equasion, but noticable performance is another and what users notice is generally meant by performance.

We were testing the maximum bandwidth of replication channel using MirrorView/S (which was 2Gbps fibre).
With 4 disk RAID1+0 LUN and 6 disk RAID5 LUN simultaneous replication the peak speed was around 540Mbps (still much less then 1Gbps).
One RAID1+0 LUN was primary on one storage and RAID5 LUN on the other. So it was full-duplex replication (270Mbps back and forth).
Calculations were conducted using 5min averages on CISCO switches.