Can 3 servers all see the same SAN Array?

[powersl]

Hi All,

I've just purchased a Dell CX300 SAN system and 3 servers, together with a fibre channel switch. The Dell engineer who installed it configured it so that each server had it's own 300gb E: drive. That seems ok but I really wanted it so that the complete 1TB was available to all 3 servers. So all 3 servers see the same data.

People are telling me that this isn't possible unless you cluster the 3 servers.

I'm looking to run Microsoft Virtual Server on Server 1 with the VHD files on the SAN. If the physical server dies, I want to be able to start up those virtual servers on server 2 etc.

I don't want anything too expensive or fancy like VMWare.

Can this be done?

Many thanks

Leonard

 

[RMGBELGIUM]

For sharing storage, you need indeed a cluster ( cluster handles scsi reservations ),and makes sure that no host accesses the storage at the same time.
Now for your problem,if you do not powerup the other hosts,you don't need a cluster ( just powerup in case of failure of server 1 ),if you want automatic failover however,you will need a cluster of your hosts OS'es,with the drive where the VHD's reside as a resource.

rgds,

R.

 

[xmsre]

At any given point in time, only one server can have exclusive access to a given piece of storage. Failover clustering solves this problem by using SCSI reservations to control which host has exclusive access at a given specific time. File level protocols solve this problem by introducing a control mechanism as well. For CIFS it would be oplocks. Replicated solutions solve the problem by inroduing multiple plexes or copies of the data.

Given your description of what you desire to accomplish, at any given point in time only one server needs access to the data. Futhtermore, you're talking about block level access to a volume or LUN. Depending on the level of automation you desire, there are several approaches. Clustering would certainly be one, and provides the highet degree of automation. Cluster failover would bring the properly configured resources and services up on another node without manual intervention. Of course, there's cost associated with clustering. For Microsoft MSCS, it means you'd have to by the enterprise instead of standard version of Windows. THere are third party clustering products that can provide failover clustering as well. Veritas Cluster Server is an example and there's the cost of the third party product to consider as well. If manual steps will suffice, then why bother? You can manually present the luns and mount them when you want to run the VHD on another server.

 

[Storageyard]

Hi, if I understand correctly, your installer set up three LUNs and distributed the LUNs to create 3 volumes, each given to one of 3 servers. You would like to share the storage so that all 3 servers have access to all 3 volumes of the storage. The concern generally is that their is protection down to the file level so the servers can share the storage without overwriting each other.
If you are running Windows or Mac OS, or even Linux, most probably you can run MetaSAN from Tiger Technology to provide a way to give access to all three servers with protection down to the file level. We set up SANs like this all the time for post production houses and others in place of clustering.
You can learn more about metaSAN at

http://www.tiger-technology.com.

Howard Solomon
Integrity Data Systems
hs at integrityds.net
+1 631.479.2401