Re: Fibre Channel Storage - Access by multiple hosts

From: Darren Dunham (ddunham_at_redwood.taos.com)
Date: 08/02/03 

Date: Sat, 02 Aug 2003 17:50:06 GMT

Jim Watson <watson@quattro666.freeserve.co.uk> wrote:
> Elias,

> Taking the multiple access to a single file out of the equation(major point
> of QFS) , do you know if, as it currently stands, the disksuite stripe will
> be accessible from the Fibre Channel to other hosts?

It's not access to the same file, its multiple mounts.

If you have a UFS or a normal VxFS filesystem on the storage, I don't
care if it's SCSI, FiberChannel, or carrier pigeon, you can't mount it
on more than one host at a time.

This is fine if you want some sort of failover arrangement, but not if
you want one host to update a filesystem and other machines to have
access to it.

Besides 'raw access' (say oracle or other databases), there are a number
of commercial 'multi-access' filesystems.

QFS
Veritas Cluster Filesystem
ADIC StorNext Filesystem.

> There is not a requirement for multiple users to acccess the same file at
> the same time. If I letf diskuite out of it and present the 10x36GB JBOD on
> the fibre-channel, other hosts can access files on the 10 disks as the disks
> are treated just like an attached SCSI disk to each machine.

As long as you're not using UFS, or as long as they're mounting
independent disks instead of all of them.

Again, this has nothing to do with FiberChannel. 

-- 
Darren Dunham                                           ddunham@taos.com
Unix System Administrator                    Taos - The SysAdmin Company
Got some Dr Pepper?                           San Francisco, CA bay area
         < This line left intentionally blank to confuse you. >

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