Data Storage - Sharing SAN Partition with multiple Linux Clients

This is Interesting: Free IT Magazines  
Home > Archive > Data Storage > June 2007 > Sharing SAN Partition with multiple Linux Clients





You are viewing an archived Text-only version of the thread. To view this thread in it's original format and/or if you want to reply to this thread please [click here]

Author Sharing SAN Partition with multiple Linux Clients
Alan Miller

2007-05-30, 7:13 pm

Hi,
We have an IBM DS4000 SAN array. We want to have two linux servers
attach to one partition and both be able to read/write to the disk at
the same time.

We created a host group and put both hosts into the same group and
gave that group a mapping to the logical drive we want them to share.
They can both connect to this drive and immediately see all the data
on that drive. However, any changes that either host makes, can only
be seen by that host. For instance if host1 creates a file, host2
cannot see it and visa versa. We are not using any cluster software.
We have QLogic 2340 fibre cards (2 in each machine) with RDAC for
failover.

Anyone know how to get this to work or is it impossible?

Thanks,
Alan
alanmiller75@gmail.com

Nik Simpson

2007-05-30, 7:13 pm

Alan Miller wrote:
> Hi,
> We have an IBM DS4000 SAN array. We want to have two linux servers
> attach to one partition and both be able to read/write to the disk at
> the same time.
>
> We created a host group and put both hosts into the same group and
> gave that group a mapping to the logical drive we want them to share.
> They can both connect to this drive and immediately see all the data
> on that drive. However, any changes that either host makes, can only
> be seen by that host.


It's worse than that, there is a good chance (somewhere north of 99.99%)
that if they both write to the disk you'll end up with a completely
trashed file system, so stop doing that right away if you care about
your data.


> Anyone know how to get this to work or is it impossible?
>


You need something like SGIs CXFS clustered file system that can manage
multiple hosts trying to update the same filesystem.
--
Nik Simpson
Rob Turk

2007-05-30, 7:13 pm

"Alan Miller" <AlanMiller75@gmail.com> wrote in message
news:1180550336.415737.208180@h2g2000hsg.googlegroups.com...
> Hi,
> We have an IBM DS4000 SAN array. We want to have two linux servers
> attach to one partition and both be able to read/write to the disk at
> the same time.
>
> We created a host group and put both hosts into the same group and
> gave that group a mapping to the logical drive we want them to share.
> They can both connect to this drive and immediately see all the data
> on that drive. However, any changes that either host makes, can only
> be seen by that host. For instance if host1 creates a file, host2
> cannot see it and visa versa. We are not using any cluster software.
> We have QLogic 2340 fibre cards (2 in each machine) with RDAC for
> failover.
>
> Anyone know how to get this to work or is it impossible?
>
> Thanks,
> Alan


Check out MetaSAN from Tiger Technology (www.tiger-technology.com). It
allows this kind of device sharing and is reasonably affordable. Disclosure:
my company resells this product in The Netherland.

Rob


osprey

2007-06-01, 7:13 am

On Wed, 30 May 2007 11:38:56 -0700, Alan Miller wrote:

> Hi,
> We have an IBM DS4000 SAN array. We want to have two linux servers
> attach to one partition and both be able to read/write to the disk at
> the same time.


You need clustering to do this, elsewhere you will trash the filesystem.
I don't know much about commercial supported clustering systems, but I've
worked with both ocfs2 and gfs2 wich are released under gpl and both seems
to works great.

Osprey
Lon

2007-06-05, 1:13 am

Nik Simpson proclaimed:

> Alan Miller wrote:
>
>
>
> It's worse than that, there is a good chance (somewhere north of 99.99%)
> that if they both write to the disk you'll end up with a completely
> trashed file system, so stop doing that right away if you care about
> your data.
>
>
>
> You need something like SGIs CXFS clustered file system that can manage
> multiple hosts trying to update the same filesystem.


.... combined with some sort of OS to OS communication to keep the two
hosts from stepping on each other. Clustering technology. Some use a
common logging disk and some use private networks, etc.
Nik Simpson

2007-06-05, 1:14 pm

Lon wrote:
> Nik Simpson proclaimed:
>
>
> ... combined with some sort of OS to OS communication to keep the two
> hosts from stepping on each other. Clustering technology. Some use a
> common logging disk and some use private networks, etc.


All of which are implicit in the term "clustered file system"
--
Nik Simpson
Andy

2007-06-11, 1:14 pm

In article <xQc9i.15934$FN5.8470@bignews7.bellsouth.net>,
n_simpson@bellsouth.net says...
>
>Lon wrote:
>
>All of which are implicit in the term "clustered file system"
>--


Polyserve is / was probably the leading product in the Linux
"clustered file system" market but now that they've been aquired by HP
I'm not sure how / where you'd buy it

if you're looking for the same ability in Windows take A LOOK AT Sanbolic


_____ . .
' \\ . . |>>
O// . . |
\_\ . . |
| | . . . |
/ | . www.EvenEnterprises.com . . . |
/ .| info@EvenEnterprises.com . . . |
/ . | 310-544-9439 / 310-544-9309 fax . . . o
----------------------------------------------------------------------
Authorized - DIRECT VAR/VAD/Distributor for new mid-high end storage
iSCSI/NAS/SAN/RAID from EMC, HP, Equallogic, Quantum, OverLand Storage

Faeandar

2007-06-11, 7:14 pm

On Mon, 11 Jun 2007 16:59:14 GMT, info@evenenterprises.com (Andy)
wrote:

>In article <xQc9i.15934$FN5.8470@bignews7.bellsouth.net>,
>n_simpson@bellsouth.net says...
>
>Polyserve is / was probably the leading product in the Linux
>"clustered file system" market but now that they've been aquired by HP
>I'm not sure how / where you'd buy it


I would think you look to HP for it, no?

>
>if you're looking for the same ability in Windows take A LOOK AT Sanbolic


Polyserve does Windows as does CXFS. In fact, the market leader in
Windows CFS is Polyserve by a huge margin.

~F

Sponsored Links






Free braindumps | Software forum | Database administration forum

Copyright 2003 - 2008 webservertalk.com