Ethernet external HardDisk.

[Mark Haney]

Felipe DOMINGUEZ wrote:
> Hello.
> 
> I continue with the problem of using an external TrekStor  Ethernet hard
> disk( which it happens to need the NDAS driver).
> 
> I did find the documentation to install and used the drivers.
> http://code.ximeta.com/trac-ndas/wiki/Usage
> 
> Every thing goes as it explains, but at the end of the instructions i found
> this:
> "An NDAS partition can only be mounted r/w from ONE Linux machine at a time,
> the rest of the machines may only use it in ro mode."
> 
>  I find it unbelievable.  The only reason I bought an Ethernet hard disk was
> to be able to use it from multiple computers in read write mode. I think I
> will have to buy a new one.
> 
> My question is: Would I have the same problem if I buy a external hard disk
> which does not need the NDAS  driver?
> Could  any one recommend me  a brand?
> What should I look at so that I do not have this problem agaion?
> Is it there any directory where we can check if a piece of hardware is linux
> compable, or where we can see other people opinion on devices?
> 
> 

Please don't top post.

Buying another ethernet hard drive won't fix your problem, unless it's 
got some NAS functionality to it and let's it export the filesystem via 
NFS (or GFS).  It's not unbelieveable to me.  It's just like any other 
hard disk, basic filesystems don't like being mounted by more than one 
host.  There /are/ exceptions (a cluster file system like GFS, or NFS) 
otherwise this drive will act like any other hard drive.

Probably the best way to get around this is to mount the drive to one 
device RW and then export it out via NFS and let the other systems mount 
the NFS device.  There isn't anything inherently wrong in doing it that way.

Do you understand why you don't want DAS to have multiple hosts with RW 
capability?  This is why NFS was developed (as well as GFS, but GFS (and 
it's brethren) were designed for SAN environments.

My suggestion is to mount the drive to one and then export NFS to the 
rest of the hosts who need RW access.  It's not that hard to do and it 
still gets you the functionality you want (albeit in a roungabout way).



-- 
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Mark Haney
Sr. Systems Administrator
ERC Broadband
(828) 350-2415

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