> ZFS will definitely benefit from battery backed RAM > on the controller > as long as the controller immediately acknowledges > cache flushes > (rather than waiting for battery-protected data to > flush to the
I am little confused with this. Do we not want the controller to ignore these cache flushes (since the cache is battery protected)? What did you mean by acknowledge? If it acknowledges and flushes the cache, then what is the benefit of the cache at all (if ZFS keeps telling to flush ever few seconds)? > The notion of "performance" is highly arbitrary since > there are > different types of performance. What sort of > performance do you need > to optimize for? It won't be a big deal. Just general web/small databases. Just wondering how much of magnitude in performance difference there is. > > Many people will recommend against using RAID5 in > "hardware" since > then zfs is not as capable of repairing errors, and > because most RAID5 > controller cards use a particular format on the > drives so that the > drives become tied to the controller brand/model and > it is not > possible to move the pool to a different system > without using an > identical controller. If the controller fails and is > no longer > available for purchase, or the controller is found to > have a design > defect, then the pool may be toast. > I use mostly DAS for my servers. This is a x4170 with 8 drive bays. So, what's the final recommendation? Should I just RAID 1 on the hardware and put ZFS on top of it? Got three options: Get the Storagetek Internal HBA (with batteries) and...: 7 disks 600gb usable ======= no hardware raid 2 rpool 3 raidz 1 hot spare 1 ssd 8 disks 600gb usable ======= 2 rpool 2 mirror + 2 mirror (the mirrors would be in hardware with zfs doing striping across the mirrors) 1 hot spare 1 ssd 8 disks 1200gb usable ======= no hardware raid 2 rpool 3 raidz + 3 raidz The hot spare and the SSD are optional and I can add them at a later point. -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
