> -----Original Message-----
> From: centos-bounces@xxxxxxxxxx
> [mailto:centos-bounces@xxxxxxxxxx] On Behalf Of John R Pierce
> Sent: Friday, February 23, 2007 11:41 AM
> To: CentOS mailing list
> Subject: Re: iSCSI, windows, & local linux access
>
> Andrew Cotter wrote:
> > Hello all,
> >
> > I am looking to build a larger array (6TB) using CentOS 4.4
> to archive
> > data to. We want to have the Windows server mount this array as a
> > local drive so we were looking at iSCSI to do it. I have
> played with
> > it in the past and gotten it to work in this combo, but I have a
> > question about access to the data on the local (Centos) machine.
> >
> > If I understand correctly, when I mount the device on
> windows, I need
> > to format the array in a format that Windows (2003 server) can
> > understand. Also, iSCSI only allows you to mount the
> array on one
> > server at a time. Once I do that and write files to this array, is
> > there anyway to access those files from the local machine
> (Centos)? I
> > may want to do things like rsync to another location, copy files to
> > another removable SATA disk, or just plain delete something.
> >
> > Is it a choice of the OS so both windows and linux can read it?
> > Little help with which one then. I know NTFS is still
> somewhat in its
> > infancy.
>
> if its mounted as a block device, nothing else should touch
> it, read OR
> write. block devices are NOT sharable, with the exception of
> specialized filesystems like GFS or IBrix Fusion Even a read only
> access would have issues with metadata consistency, if windows is
> updating a directory or MFT or whatever, linux could see stale/mixed
> data and would just throw up
Technically yes, if the volume has long periods of no activity though
there should be no problem in taking a snapshot and mounting that.
Understand that if the volume is being actively used by a backup process
the data contained therein will not be consistent, but it will not harm
the production volume, just the snapshot will not be considered prime.
> the only 'safe' way to do it would be for the windows machine
> to share
> the logical file system, and have the linux system access it as a
> smbmount via samba.
> or use replication running on the windows server (rsync
> from mingw, etc)
Yes sharing it and mounting it back via CIFS is more reliable for a
highly active volume, but if you plan to then copy-out data over the
network it will slow things down to a crawl.
> Windows 2003 server has its own snapshotting capabilities, btw.
Which IMHO are crap. If it's backup jobs that are accessed during a run,
but otherwise sit there unused, then you can snapshot them off LVM
fairly safely.
-Ross
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