shared scsi, external storage, vtrack

Hi all.

I have two identical servers with CentOS (aka RHEL4.1) and one external data storage Vtrak 8110 (http://www.promise.com/product/product_detail_eng.asp?segment=VTrak&product_id=135) which connected by two scsi cables to this servers. I need to setup something called "shared scsi" but i haven't any experience with such things. My main task is build HA system (Vtrak used for postgresql databases). Can anybody help me with docs, HOWTOs and other?

You'll need to do this one of two ways. First (simplest, most catastrophic error-prone) either make *CERTAIN* the systems NEVER, EVER, simultaneously mount the storage volumes, or, use a multi-host disk filesystem such as Sistina's GFS.

outside of that there's nothing special to be done. one host has to be passive/inactive at all times in the first option, the second option means you can't use LVM, since, unless I'm mistaken, LVM has *no* capability for shared storage mediums.

Now most of these products can also be setup so that each host has their own storage space, and therefore they work like any other disk subsystem, each host only sees what they can access, but it sounds like you're not interested in that.

In any case, with postgresql, you're not going to be able to share their backend storage, so you'll have to have two totally separate storage areas if you want two live servers, or, you have one live, and one passive standby.

--
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