On 12 apr 2010, at 19.10, Kyle McDonald wrote: > On 4/12/2010 9:10 AM, Willard Korfhage wrote: >> I upgraded to the latest firmware. When I rebooted the machine, the pool was >> back, with no errors. I was surprised. >> >> I will work with it more, and see if it stays good. I've done a scrub, so >> now I'll put more data on it and stress it some more. >> >> If the firmware upgrade fixed everything, then I've got a question about >> which I am better off doing: keep it as-is, with the raid card providing >> redundancy, or turn it all back into pass-through drives and let ZFS handle >> it, making the Areca card just a really expensive way of getting a bunch of >> SATA interfaces? >> > > AS one of the other posters mentioned there may be a third way that > might give you something close to "the best of both worlds". > > Try using the Areca card to make 12 single disk RAID 0 LUNs, and then > use those in ZFS. > I'm not sure of the definition of 'passthrough', but if it disables any > battery backed cache that the card may have, then by setting up 12 HW > RAID LUNs instead, you it should give you an improvement by allowing the > Card to cache writes. > > The one downside of doing this vs. something more like 'jbod' is that if > the controller dies you will need to move the disks to another Areca > controller, where as with 12 'jbod' connections you could move them to > pretty much any controller you wanted.
And that if you use the write cache in the controller and the controller dies, parts of your recently written data is only in the dead controller, and your pool may be more or less corrupt and may have to be rolled back a few versions to be rescued or may be not rescuable at all. This may may not be acceptable. /ragge _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
