HPE EVA Storage

SAN Migration Advice - Flash Cut?

 
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Alzhy
Honored Contributor

SAN Migration Advice - Flash Cut?

Dual Fabric casacaded -- total ~ 200 ports per fabric led by dual SW12000's.

We got a new fully populated pair of SW48000s. Our team is divided on how to do a flash cut.

Poponent A:
Hook up the SW48Ks to the Fabric and migrate over all ports to the SW48K Directors. Then ditch the old SAN.

Proponent B:
Do not hook up the 48Ks to the existing Fabric. Run new cables. Redefine all aliases and zones and move over the ports...

Bot will be cold cuts.

I'm for Method B so all zones and aliases will be re-defined and whaever stale aliases, zones can be rid out of the new Fabric.

Any inputs?
Hakuna Matata.
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Del_3
Trusted Contributor
Solution

Re: SAN Migration Advice - Flash Cut?

Both will work. What are your OS's?
Alzhy
Honored Contributor

Re: SAN Migration Advice - Flash Cut?

vMware, Solaris, VMS, HP-UX....
We can do it COLD.
Hakuna Matata.
Del_3
Trusted Contributor

Re: SAN Migration Advice - Flash Cut?

Remember your HPUX device files are based on the FCID. If you change the domain of the switch or port connection of your HPUX hosts you will have to vgexport/import. This may help your decision.
krusty
Honored Contributor

Re: SAN Migration Advice - Flash Cut?

I have a third option you may want to consider. Disconnect all ports on one of the fabrics and migrate them to the new 48K's with all the new alisas / zones / configs. Then after the new fabric is verified, recalbe the other 12K and move the cables to the other 48K.

You could logically or with failover move the ports over between fabrics. I've migrated switches online in this fashion on HP-UX servers (vgreduces and vgextends). This gives you the a little more time and no downtime, but would required more planning. Just an idea you may want to think about....

Cheers,

Curt
"In Vino Veritas"
Vasiliy Karpov
Trusted Contributor

Re: SAN Migration Advice - Flash Cut?

We did SAN migration to new/unused switches online. But this procedure may be helpful for you too.

Carefully analyzing our environment decided to hook-up old and new fabrics and then migrate ports.

Procedure:

1. check and cleanup zoning on both fabrics of both SANs; (remove old/unused zones, check corresponding zones in fabrics for redundancy)
2. check and redefine all aliases from port-based to wwn-based; (this procedure is non-disruptive, you add new wwn to alias, and then remove old wwn/port_def... doing so helps to save some time and skip annoying reconfiguration operation during ports reconnection - just unplug from one switch, plug to another and all works)
3. reconfigure switches and domain IDs as necessary;
4. interconnect fabrics, verify zone transfer/merge;
5. reconnect ports for fabric1;
6. verify paths on all hosts;
7. reconnect ports for fabric2;
8. verify paths on all hosts;

You have to be careful, and take into consideration next few things:

Device files on Tru64 systems are based on the FCID. This means if you reconnect storages, tape libraries, etc to another switch/port - hardware paths on hosts will change! It this case you will have to re-import new paths to your volume manager or multipath software. (spmgr -discover or vgextend/vgreduce) The same apply if you change domain id.

From our own experience: if you reconnect HPUX/Windows/Linux/Solaris servers to another switch/port ) assuming all aliases are wwn-based, and you are not rescanning devices in the middle of reconnection process) - HW paths (device files) will not change.
Vasiliy Karpov
Trusted Contributor

Re: SAN Migration Advice - Flash Cut?

Please, assign points to answers!
Uwe Zessin
Honored Contributor

Re: SAN Migration Advice - Flash Cut?

> Device files on Tru64 systems are based on the FCID.

I beleive you are talking about HP-UX or IBM-AIX.

Tru64 Unix uses the LUN WWN in SCSI page 83(16) for persistent binding; T64 version 5 does not use Secure Path - the multipath feature is embedded in the operating system.
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Vasiliy Karpov
Trusted Contributor

Re: SAN Migration Advice - Flash Cut?

> I beleive you are talking about HP-UX or
> IBM-AIX.

Sorry, I mean HP-UX...
Alzhy
Honored Contributor

Re: SAN Migration Advice - Flash Cut?

Thanks for your Inputs.

On HP-UX and SOlaris, we will not have the problem of changing cXtYdZ as we're using VxVM on all. vMware and VMS won;t have any issues with the Flash COld Cut.

We've decided to hook up the 12K to the 48K just to propagate the aliases and zones and flash cut each fabric one after the other.

We zone by WWID so we expect it to be seamless.

Hakuna Matata.