On 6/29/10, Karanbir Singh <mail-lists at karan.org> wrote: > Depends on how you set it up, if you have 2 machines ( disk nodes ), > exporting iscsi. 1 machine ( data node ) doing the import and sets up a > raid1; you can afford to have one of those two machines down. You *cant* > afford to have the data-node down. Thats where the filesystem lives. You > can potentially have the same disks from the disk-nodes imported to a > standby data node using something like drbd over the mdraid setup. > Alternatively, you can look at using a clustered filesystem and have it > go X way. But then you may as well use something like gnbd with gfs2 > instead(!). Looking up gfs2 was what lead me to glusterFS actually and because glusterFS had all the RAID stuff pointed out upfront, I stopped reading about gfs2. Googling gluster then lead to openFiler which then seemed like a simpler way to achieve the objectives. > Yes, lots of options and different ways of doing the same thing. So > start at the top, make a list of all the problems you are trying to > solve. then split that into 3 segments: > - Must have > - Good to have > - Dont really need > Must have - low cost, clients have a budget which was why mirroring all the machines is not an option - data redundancy, application servers can go down, but data must not be lost/corrupted. - expandable capacity - works with VM - doable by noob admin :D Good to have - able to add/restore capacity without need to take down the whole setup - application server redundancy - webUI for remote management I've done mostly LVM + mdraid setup so far, hence the openfiler + remote iSCSI raid route looks to fit the above and is the most simple (less new things to learn/mess up) option compared to most other which needs multiple components to work together it seems.