Mirroring two raid systems in Linux

[Murray Itkin]

We have a critical data system. It's currently hosted on two raid chassis' on a Solaris host using zpool & zfs to maintain a physical mirror. Works fine, but we are abandoning Solaris and therefore zfs.

I'm setting up a DL380 running LInux with two other raid chassis'. The question is... What do I use to mirror these two raid chassis' on Linux. I could use LVM's mirroring option, but I seem to need a third small physical partition for a mirror log. Or I could use mdadm and that use LVM on top. This would eliminate the the need for the third small physical partition, but I'm concerned about how mdadm would handle the multipathing of these Fibre channel attached raid systems.

Please note that safety of the data is most important in this design, not performance.

[Alzhy]

Murray,

What kind of RAID Chassis do you have? Are they Fibre JBODs or controller based (dual or an MSL/MSA?)

If they're simply JBODs and are "dual ported" FC Connections, then I can suggest 2 recipes:

Recipe #1
Still use ZFS (albeit ZFS-fuse) and there's a very high probability your "zpool" will still be recognizable (assuming your RAID CHassis disks are JBODS. Installation of zfs-fuse is easy and erauired no reboot even. http://zfs-fuse.net/. I find the current release 0.6.9 to be super stable enough I use it on my HomeBrew NAS as well as several clients.


Recipe #2:
Use mdadm+LVM. You can do either RAID0+1 or RAID1+0 or even a mirror of 2 RAID5's. Up to you.

Make sure though your "RAID CHASSIS", if those are dual ported, is fully configured with device multipath.