[linux-lvm] LVM & GFS?

[linux-lvm] LVM & GFS?

[Lars O. Grobe]

Hi!

I am currently running a Linux fileserver with LVM 1.x, on kernel 2.4.19. The 
storage system consists of two scsi-raid5 (ibm serveraid 4m) both as physical 
volumes in a vg containing the volumes we share with netatalk and samba to 
our clients.

We are going to buy a new fileserver system now. As we need high-availability 
in future (the new server will hold all data of the faculty of architecture 
here), we are going to implement a failover-scenario with to nodes accessing 
a fibrechannel storage with redundant paths'. We didn't decide so for wether 
to use ibm, compaq ore fujitsu-siemens hardware, but all three offer these 
solutions.

As I know about gfs, I wonder how difficult it would be to add load balancing 
to this configuration by using gfs (so far we are on reiserfs 3.6x). Would we 
still need LVM (and is this a common combination)? I use LVM to give any 
department it's own volume, so that filesystem settings are made on a per 
department base, and I would like to keep this.

I am not sure wether this is OT here, but as I have been on this list for a 
while now, I would like to ask which contact could help me further. I will 
download the eval version of gfs5.1 now and install it on my laptop - one 
node ;-)

CU, Lars.

Re: [linux-lvm] LVM & GFS?

[Heinz J . Mauelshagen]

On Tue, Nov 26, 2002 at 01:02:22PM +0100, Lars O. Grobe wrote:
> Hi!
> 
> I am currently running a Linux fileserver with LVM 1.x, on kernel 2.4.19. The 
> storage system consists of two scsi-raid5 (ibm serveraid 4m) both as physical 
> volumes in a vg containing the volumes we share with netatalk and samba to 
> our clients.
> 
> We are going to buy a new fileserver system now. As we need high-availability 
> in future (the new server will hold all data of the faculty of architecture 
> here), we are going to implement a failover-scenario with to nodes accessing 
> a fibrechannel storage with redundant paths'. We didn't decide so for wether 
> to use ibm, compaq ore fujitsu-siemens hardware, but all three offer these 
> solutions.
> 
> As I know about gfs, I wonder how difficult it would be to add load balancing 
> to this configuration by using gfs (so far we are on reiserfs 3.6x). Would we 
> still need LVM (and is this a common combination)? I use LVM to give any 
> department it's own volume, so that filesystem settings are made on a per 
> department base, and I would like to keep this.

Yes, you can achieve load balancing using GFS on both nodes.
_Plus_ it gives you much better resilience WRT server failures presuming
your clients support failover (any of the 2 nodes can crash and the service
is still available). Such configurations are the ones we can leverage
with GFS :)

Yes, you can use LVM in combination with GFS _but_ because LVM is a single
host volume manager you need to use its 'static mode' in order to access
its volume groups throughout the cluster in order to run GFS on top of it.
You need to unmount all GFS file systems on all nodes and deactivate LVM
on all but one in order to change the LVM configuration though.

We are working on LVM2 which is the base for CLVM (Cluster LVM)
planned for next year. CLVMs major advantage is for sure that all LVM commands
will run cluster wide and that all changes to volume groups and/or logical
volumes are visible in the cluster immediately.
You are able to do a smooth upgrade from LVM1+GFS to
CLVM+GFS because it supports the LVM1 metadata. IOW: no need for
backup+reinstall+reconfigure+restore, just SW upgrade.

> 
> I am not sure wether this is OT here, but as I have been on this list for a 
> while now, I would like to ask which contact could help me further. I will 
> download the eval version of gfs5.1 now and install it on my laptop - one 
> node ;-)

For now, GFS comes with a simple volume manager called POOL which enables you
to group whole disks together. You can use that one _or_ LVM1 in 'static mode'.
Upgrade to CLVM is potentially easier the second way though we plan to support
POOL -> CLVM upgrades as well.

Feel free to contact sales@sistina.com for further information.

> 
> CU, Lars.
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Regards,
Heinz    -- The LVM Guy --

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen@Sistina.com                           +49 2626 141200
                                                       FAX 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: [linux-lvm] LVM & GFS?

[Lars Grobe]

Hi, thank you for your reply!

OK, I think it is just what we want ... as I am sitting in front of a server
test installation at fujitsu-siemens RIGHT NOW, with a fibrechannel storage
attached to two Linux-nodes.... ONE hint how to install gfs modules on top of
a SuSE 7.3 might be quite helpful ;-)))

So if anybody out there is reading this and has any experiences with gfs on
SuSE (I could only download the RedHat-rpms at Sistina), PLEASE answer me
fast ;-)

TNX, CU, Lars.

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