VMWare & SAN Experts...

BoomAM

BoomAM

BoomAM

Soldato
Joined
5 Jul 2003
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Morning all,
Quick question, we currently have a Dell MD3200 ExSAS SAN presenting 4 LUNs to a ESX 4.1 server.
I seem to remember when i originally put in the SAN something about 'multi homing for VM Hosts', im fairly sure i would have enabled it but i cant find anything in the SAN's settings nor Dells manuals to suggest this setting either way.

Ive just built a second ESX 4.1 host to add to the SAN that i want to read the same LUNs (not at the same time obviously :p).

Am i likely to get any data corruption issues or issues of any kind?

And does anyone know where this 'multihome' thing is? or how to check its on?

Thanks in advance all.
 
When you goto present the LUNs to the second host it will warn you that the servers must be cluster aware or data corruption may occur - aknowledge that and continue - thats on all SANs i've used with VMware :)

Not sure if you need to set host persona's or such on the Dell kit - presume its rebranded Equallogic?
 
Teledude said:
When you goto present the LUNs to the second host it will warn you that the servers must be cluster aware or data corruption may occur - aknowledge that and continue - thats on all SANs i've used with VMware :)
Click to expand...
Well as the SAN was presetup to present the LUNs, they have just appeared on the new host (no VMs in used on the new host yet).

Using two free ESXi licences, as long as i dont use the same datastore on two hosts at the same time, or try it, i should be fine shouldnt i?
Or is there a setting in ESXi i need to enable?

Not sure if you need to set host persona's or such on the Dell kit - presume its rebranded Equallogic?
Click to expand...
I know when i add the host i can specify Windows/VMWare/generic, which i obviously select VMWare.
But i could have sworn that on the initial install there was something about multi homing...
 
No potential corruption issues. VMFS is a clustered filesystem designed for having multiple hosts access the same LUN.
 
Teledude said:
When you goto present the LUNs to the second host it will warn you that the servers must be cluster aware or data corruption may occur - aknowledge that and continue - thats on all SANs i've used with VMware :)

Not sure if you need to set host persona's or such on the Dell kit - presume its rebranded Equallogic?
Click to expand...

The MD3200 series is mainly OEM'd from LSI (based on the CTS 2600), though they've just sold the Engenio business (which includes the CTS 2600) to NetApp.
 
AlexD said:
No potential corruption issues. VMFS is a clustered filesystem designed for having multiple hosts access the same LUN.
Click to expand...
1000000000% sure?
I know i am, its the SAN side im unsure of. :p

So what was this multi home/host thing i remember seeing when i setup the MD3200?
 
I've never used this SAN product but if its like most SAN systems the most logical design of this is that you assign LUNs to the host group and assign hosts to the host group.

Normaly you restrict LUNs to specific hosts, in the case of most systems this is to prevent other systems damaging an already mounted LUN on another host.
 
That looks fine, if that sharing option is set it should then allow access to a volume from different HBAs. Just make sure the access restrictions are set in such a way that both HBAs can connect.
I know on Equallogic PS series you have the choice of CHAP, IP Address/range and initiator name, or indeed any combination of those and you can just add more to the list as required. I'd assume being a Dell unit there would be some similar options in your config.
 
from what I can remember from my VCP course as long as the LUN isn't used for booting the OS on the ESX server then you are fine to present it to all the ESX boxes. This will allow you to use VMotion (providing you have the license for it)
 
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